Wikipedia:Writing better articles
This page advises on article layout and style, and on making an article clear, precise and relevant to the reader.
Good articles start with introductions, continue with a clear structure, and end with standard appendices such as references and related articles.
Articles start with a lead section (WP:CREATELEAD) summarising the most important points of the topic. The lead section is the first part of the article; it comes above the first header, and may contain a lead image which is representative of the topic, and/or an infobox that provides a few key facts, often statistical, such as dates and measurements.
The lead should stand on its own as a concise overview of the article's topic, identifying the topic, establishing context, and explaining why the topic is notable. The first few sentences should mention the most notable features of the article's subject – the essential facts that every reader should know. Significant information should not appear in the lead if it is not covered in the remainder of the article; the article should provide further details on all the things mentioned in the lead. Each major section in the article should be represented with an appropriate summary in the lead, including any prominent controversies; but be careful not to violate WP:Neutral point of view by giving undue attention to less important controversies, information, or praise in the lead section. As in the body of the article itself, the emphasis given to material in the lead should roughly reflect its importance to the topic, according to reliable, published sources.
As a rough guide to size, a lead section should generally contain no more than four well-composed paragraphs and be carefully sourced as appropriate.
Sometimes, the first section after the lead is a broad summary of the topic, and is called "Overview", although more specific section titles and structures are generally preferred.
Paragraphs should be short enough to be readable, but long enough to develop an idea. Overly long paragraphs should be split up, as long as the cousin paragraphs keep the idea in focus.
One-sentence paragraphs are unusually emphatic, and should be used sparingly.
Some paragraphs are really tables or lists in disguise. They should be rewritten as prose or converted to their unmasked form. Wikipedia:When to use tables and Wikipedia:Embedded list offer guidance on the proper use of these elements.
Headings help clarify articles and create a structure shown in the table of contents. To learn about how the MediaWiki software uses sections, see Help:Section.
Headings should not be Wikilinked. This is because headings in themselves introduce information and let the reader know what subtopics will be presented; Wikilinks should be incorporated in the text of the section.
If the article can be illustrated with pictures, find an appropriate place to position these images, where they relate closely to text they illustrate. If there might be doubt, draw attention to the image in the text (illustration right). For more information on using pictures, see Wikipedia:Layout § Images and Wikipedia:Picture tutorial.
As explained in more detail at , optional appendix sections containing the following information may appear after the body of the article in the following order:
With some exceptions, any links to sister projects appear in further reading or external links sections. Succession boxes and navigational footers go at the end of the article, following the last appendix section, but preceding the category and interwiki templates.
Excessively long articles should usually be avoided. Articles should ideally contain less than 50,000 characters of text. When articles grow past this amount of readable text, they can be split into smaller articles to improve readability and ease of editing, or may require trimming to remain concise. The headed sub-section should be retained, with a concise version of what has been removed under an italicized header, such as Main article: History of Ruritania (a list of templates used to create these headers is available at Category:Wikipedia page-section templates). Otherwise, context is lost and the general treatment suffers. Each article on a subtopic should be written as a stand-alone article—that is, it should have a lead section, headings, et cetera.
When an article is long and has many sub articles, try to balance the main page. Do not put undue weight into one part of an article at the cost of other parts. In shorter articles, if one subtopic has much more text than another subtopic, that may be an indication the subtopic should have its own page, with only a summary presented on the main page.
Wikipedia articles tend to grow in a way that leads to the natural creation of new articles. The text of any article consists of a sequence of related but distinct subtopics. When there is enough text in a given subtopic to merit its own article, that text can be summarized in the present article and a link provided to the more detailed article. Cricket is an example of an article covering subtopics: it is divided into subsections that give an overview of the sport, with each subsection leading to one or more subtopic articles.
These styles are summary style, which is the arrangement of a broad topic into a main article and side articles, each with subtopical sections; and the inverted pyramid style (or news style, though this term is ambiguous), which prioritizes key information to the top, followed by supporting material and details, with background information at the bottom.
A feature of both styles, and of all Wikipedia articles, is the presence of the lead section, a summarizing overview of the most important facts about the topic. The infobox template found at the top of many articles is a further distillation of key points.
The exact organizing principle of a particular summary-style article is highly context-dependent, with various options, such as chronological, geographical, and alphabetical (primarily in lists), among others.
Some Wikipedians prefer using the inverted pyramid structure of journalism. This information presentation technique is found in short, direct, front-page newspaper stories and the news bulletins that air on radio and television. This is a style used only within a single article, not across a category of them.
The main feature of the inverted pyramid is placement of important information first, with a decreasing importance as the article advances. Originally developed so that the editors could cut from the bottom to fit an item into the available layout space, this style encourages brevity and prioritizes information, because many people expect to find important material early, and less important information later, where interest decreases.
Encyclopedia articles are not required to be in inverted pyramid order, and often aren't, especially when complex. However, a familiarity with this convention may help in planning the style and layout of an article for which this approach is a good fit. Inverted-pyramid style is most often used with articles in which a chronological, geographical, or other order will not be helpful. Common examples are short-term events, concise biographies of persons notable for only one thing, and other articles where there are not likely to be many logical subtopics, but a number of facts to prioritize for the reader.
The lead section common to all Wikipedia articles is, in essence, a limited application of the inverted pyramid approach. Virtually all stub articles should be created in inverted-pyramid style, since they basically consist of just a lead section. Consequently, many articles begin as inverted-pyramid pieces and change to summary style later as the topic develops, often combining the approaches by retaining a general inverted pyramid structure, but dividing the background material subtopically, with summary pointers to other articles.
. Articles and other encyclopedic content should be written in a formal tone. Standards for formal tone vary a bit depending upon the subject matter but should usually match the style used in Featured- and Good-class articles in the same category. Encyclopedic writing has a fairly academic approach, while remaining clear and understandable. Formal tone means that the article should not be written using argot, slang, colloquialisms, doublespeak, legalese, or jargon that is unintelligible to an average reader; it means that the English language should be used in a businesslike manner.
Articles should not be written from a first- or second-person perspective. In prose writing, the first-person (I/me/my and we/us/our) point of view and second-person (you and your) point of view typically evoke a strong narrator. While this is acceptable in works of fiction and in monographs, it is unsuitable in an encyclopedia, where the writer should be invisible to the reader. Moreover, pertaining specifically to Wikipedia's policies, the first person often inappropriately implies a point of view inconsistent with the neutrality policy, while second person is associated with the step-by-step instructions of a how-to guide, which Wikipedia is not. First- and second-person pronouns should ordinarily be used only in attributed direct quotations relevant to the subject of the article.
As with many such guidelines, however, there can be occasional exceptions. For instance, the "inclusive we" is widely used in professional mathematics writing, and though discouraged on Wikipedia even for that subject, it has sometimes been used when presenting and explaining examples. Use common sense to determine whether the chosen perspective is in the spirit of the guidelines.
Gender-neutral pronouns should be used (or pronouns avoided) where the gender is not specific.
As a matter of policy, Wikipedia is not written in news style (in any sense other than some use of the inverted pyramid, above), including tone. The encyclopedic and journalistic intent and audience are different. Especially avoid bombastic wording, attempts at humor or cleverness, reliance on primary sources, editorializing, recentism, pull quotes, journalese, and headlinese.
Similarly, avoid news style's close sibling, persuasive writing, which has many of those faults and more of its own, most often various kinds of appeals to emotion and related fallacies. This style is used in press releases, advertising, op-ed writing, activism, propaganda, proposals, formal debate, reviews, and much tabloid and sometimes investigative journalism. It is not Wikipedia's role to try to convince the reader of anything, only to provide the salient facts as best they can be determined, and the reliable sources for them.
Another error of writing approach is attempting to make bits of material "pop" (an undue weight problem), such as with excessive emphasis, over-capitalization, use of contractions, unnecessary acronyms and other abbreviations, the inclusion of hyperbolic adjectives and adverbs, or the use of unusual synonyms or loaded words. Just present the sourced information without embellishment, agenda, fanfare, cleverness, or conversational tone.
An extreme example of hyperbole and emphatic language taken from Star Canopus diving accident as of 28 December 2019 (fixed in the next two revisions) reads:Miraculously both divers survived the 294-foot fall, but now they faced a harrowing predicament. ... Helplessly trapped, with nothing to keep them warm, ... all they could do was huddle together and pray that rescuers would find them in time. ... But time was not on their side.
See Wikipedia:Manual of Style/Words to watch for other examples. Avoid using words and phrases like terrible, rising star, curiously, championed the likes of or on the other side of the pond, unless part of a quotation or stated as an external viewpoint.
Punctuation marks that appear in the article should be used only per generally accepted practice. Exclamation marks (!) should be used only if they occur in direct quotations.There are many environmental concerns when it comes to industrial effluent. How can these be solved? Well, one solution involves ...
Rhetorical questions can occasionally be used, when appropriate, in the presentation of material, but only when the question is asked by the material under consideration, not being asked in Wikipedia's own voice.One model of policy analysis is the "five-E approach", which consists of examining a policy in terms of:How much work does or will it entail? Are there significant costs associated with this solution, and are they worth it? ...
Not all tone flaws are immediately obvious as bias, original research, or other policy problems but may be relevance, register, or other content-presentation issues. A common one is the idea, often taught to debate students, that each section or even paragraph should introduce a key statement (a thesis) followed by supporting evidence in additional sentences and finish with a recapitulation of the original thesis in different wording. This style is redundant and brow-beating and should not be used in encyclopedic writing.Leibniz and Newton are usually both credited with the invention of calculus.As such, today both Newton and Leibniz are given credit for developing calculus independently.Today, Leibniz and Newton are usually both given credit for independently inventing and developing calculus.
A related presentation problem is "info-dumping" by presenting information in the form of a long, bulleted list when it would be better as normal prose paragraphs. This is especially true when the items in the list are not of equal importance, or are not really comparable in some other way, and need context. Using explanatory prose also helps identify and remove trivia; if we cannot explain to readers why something is important, then it is not important.
Wikipedia is an international encyclopedia. People who read Wikipedia have different backgrounds, education and opinions. Make your article accessible and understandable for as many readers as possible. Assume readers are reading the article to learn. It is possible that the reader knows nothing about the subject, so the article needs to explain the subject fully.
Avoid using jargon whenever possible. Consider the reader. An article entitled "Use of chromatic scales in early Baroque music" is likely to be read by musicians, and technical details and terms are appropriate, linking to articles explaining the technical terms. On the other hand, an article entitled "Baroque music" is likely to be read by laypersons who want a brief and plainly written overview, with links to available detailed information. When jargon is used in an article, a brief explanation should be given within the article. Aim for a balance between comprehensibility and detail so that readers can gain information from the article.
Here are some thought experiments to help you test whether you are setting enough context:
Remember that every Wikipedia article is tightly connected to a network of other topics. Establishing such connections via wikilink is a good way to establish context. Because Wikipedia is not a long, ordered sequence of carefully categorized articles like a paper encyclopedia, but a collection of randomly accessible, highly interlinked ones, each article should contain links to more general subjects that serve to categorize the article. When creating links, do not go overboard, and be careful to make your links relevant. It is not necessary to link the same term twelve times (although if it appears in the lead, then near the end, it might be a good idea to link it twice).
Avoid making your articles orphans. When you write a new article, make sure that one or more other pages link to it, to lessen the chances that your article will be orphaned through someone else's refactoring. Otherwise, when it falls off the bottom of the Recent Changes page, it will disappear into the Mariana Trench. There should always be an unbroken chain of links leading from the Main Page to every article in Wikipedia; following the path you would expect to use to find your article may give you some hints as to which articles should link to your article.
State facts that may be obvious to you, but are not necessarily obvious to the reader. Usually, such a statement will be in the first sentence or two of the article. For example, consider this sentence:The Ford Thunderbird was conceived as a response to the Chevrolet Corvette and entered production for the 1955 model year.
Here no mention is made of the Ford Thunderbird's fundamental nature: it is an automobile. It assumes that the reader already knows this—an assumption that may not be correct, especially if the reader is not familiar with Ford or Chevrolet. Perhaps instead:The Ford Thunderbird was a car manufactured in the United States by the Ford Motor Company.
However, there is no need to go overboard. There is no need to explain a common word like "car". Repetition is usually unnecessary, for example:Shoichi Yokoi was a Japanese soldier in Japan who was drafted into the Imperial Japanese Army in 1941.
As explained in more detail at Wikipedia:Lead section § Introductory text, all but the shortest articles should start with introductory text (the "lead"). The lead should establish significance, include mention of consequential or significant criticism or controversies, and be written in a way that makes readers want to know more. The appropriate length of the lead depends on that of the article, but should normally be no more than four paragraphs. The lead itself has no heading and, on pages with more than three headings, automatically appears above the table of contents, if present.
Normally, the opening paragraph summarizes the most important points of the article. It should clearly explain the subject so that the reader is prepared for the greater level of detail that follows. If further introductory material is appropriate before the first section, it can be covered in subsequent paragraphs in the lead. Introductions to biographical articles commonly double as summaries, listing the best-known achievements of the subject. Because some readers will read only the opening of an article, the most vital information should be included.An electron is a subatomic particle that carries a negative electric charge.The chief electrical characteristic of a dynamic loudspeaker's driver is its electrical impedance as a function of frequency.Las Meninas (Spanish for The Maids of Honour) is a 1656 painting by Diego Velázquez, ..."Yesterday" is a pop song originally recorded by The Beatles for their 1965 album Help!.Sodium hydroxide (NaOH), also known as lye, caustic soda and (incorrectly, according to IUPAC nomenclature) sodium hydrate, is ...Arugam Bay is a bay situated on the Indian Ocean in the dry zone of Sri Lanka's southeast coast.
Then proceed with a description. Remember, the basic significance of a topic may not be obvious to nonspecialist readers, even if they understand the basic characterization or definition. Tell them. For instance:
If the article is long enough for the lead section to contain several paragraphs, then the first paragraph should be short and to the point, with a clear explanation of what the subject of the page is. The following paragraphs should give a summary of the article. They should provide an overview of the main points the article will make, summarizing the primary reasons the subject matter is interesting or notable, including its more important controversies, if there are any.
The appropriate length of the lead section depends on the total length of the article. As a general guideline:
The sequence in which you edit should usually be: first change the body, then update the lead to summarize the body. Several editors might add or improve some information in the body of the article, and then another editor might update the lead once the new information has stabilized. Don't try to update the lead first, hoping to provide direction for future changes to the body. There are three reasons why editing the body first and then making the lead reflect it tends to lead to better articles.
First, it keeps the lead in sync with the body. The lead, being a summary of the article, promises that the body will deliver fuller treatment of each point. Generally, wiki pages are imperfect at all times, but they should be complete, useful articles at all times. They should not contain "under construction" sections or refer to features and information that editors hope they will contain in the future. It's much worse for the lead to promise information that the body does not deliver than for the body to deliver information that the lead does not promise.
Second, good ways to summarize material usually only become clear after that material has been written. If you add a new point to the lead before it's covered in the body, you only think you know what the body will eventually contain. When the material is actually covered in the body, and checked and improved, usually by multiple editors, then you know. (If having a rough, tentative summary helps you write the body, keep your own private summary, either on your computer or in your User space.)
Third, on contentious pages, people often get into edit wars over the lead because the lead is the most prominent part of the article. It's much harder to argue constructively over high-level statements when you don't share common understanding of the lower-level information that they summarize. Space is scarce in the lead, so people are tempted to cram too much into one sentence, or pile on lots of references, in order to fully state and prove their case—resulting in an unreadable lead. In the body, you have all the space you need to cover subtleties and to cover opposing ideas fairly and in depth, separately, one at a time. Once the opposing ideas have been shaken out and covered well in the body, editing the lead without warring often becomes much easier. Instead of arguing about what is true or what all the competing sources say, now you are just arguing over whether the lead fairly summarizes what's currently in the body.
It is fine to include foreign terms as extra information, but avoid writing articles that can only be understood if the reader understands the foreign terms. Such words are equivalent to jargon, which should be explained somehow. In the English-language Wikipedia, the English form does not always have to come first: sometimes the non-English word is better as the main text, with the English in parentheses or set off by commas after it, and sometimes not. For example, see Perestroika.
English title terms taken from a language that does not use the Roman alphabet can include the native spelling in parentheses. See, for example, I Ching (simplified Chinese: 易经; traditional Chinese: 易經; pinyin: Yìjīng) or Sophocles (Greek: Σοφοκλῆς). The native spelling is useful for precisely identifying foreign words, since transliterations may be inaccurate or ambiguous. Foreign terms within the article body do not need native spellings if they can be specified as title terms in separate articles; just link to the appropriate article on first occurrence.
If possible, avoid presenting information with color only within the article's text and in tables.
Color should only be used sparingly, as a secondary visual aid. Computers and browsers vary, and you cannot know how much color, if any, is visible on the recipient's machine. Wikipedia is international: colors have different meaning in different cultures. Too many colors on one page look cluttered and unencyclopedic. Specifically, use the color red only for alerts and warnings.
Awareness of color should be allowed for low-vision viewers: poor lighting, color blindness, dark or overbright screens, and the wrong contrast/color settings on the display screen.
Articles should use only necessary words. This does not mean using fewer words is always better; rather, when considering equivalent expressions, choose the more concise.
Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that every word tell.
Reduce sentences to the essentials. Wordiness does not add credibility to Wikipedia articles. Avoid circumlocutions like "due to the fact that" in place of "because", or "at the present time" for "currently". Ongoing events should be qualified with "as of 2020". Wikipedia "grammar bots" will replace these types of expressions with correct wording.
When the principle of least astonishment is successfully employed, information is understood by the reader without struggle. The average reader should not be shocked, surprised, or confused by what they read. Do not use provocative language. Instead, offer information gently. Use consistent vocabulary in parts that are technical and difficult. To work out which parts of the sentence are going to be difficult for the reader, try to put yourself in the position of a reader hitherto uninformed on the subject.
You should plan your page structure and links so that everything appears reasonable and makes sense. A link should not take readers to somewhere other than where they thought it would go.
Avoid Easter egg links, which require the reader to open them before understanding what's going on. Instead, use a short phrase or a few words to describe what the link will refer to once it's opened.
Similarly, make sure that concepts being used as the basis for further discussion have already been defined or linked to a proper article. Explain causes before consequences and make sure your logical sequence is clear and sound, especially to the layperson.
Ensure that redirects and hatnotes that are likely to be useful are in place. If a user wants to know about the branch of a well-known international hotel chain in the French capital, they may type "Paris Hilton" into the search box. This will, of course, take them to the page associated with a well-known socialite called Paris Hilton. Luckily, though, a hatnote at the top of that article exists in order to point our user to an article which they will find more useful.
We cannot control all astonishment – the point of an encyclopedia is to learn things, after all. But limiting the surprises our readers find within our articles' text will encourage rather than frustrate our readers.
Phrases such as refers to, is the name of, describes the, or is a term for are sometimes used inappropriately in the first sentence of Wikipedia articles. For example, the article Computer architecture once began with the sentence, ""Computer architecture refers to the theory behind the design of a computer.
That is not true: Computer architecture is the theory. The words "computer architecture" refer to the theory, but the article is not about the words; it is about the theory.
Thus it is better to say, "Computer architecture is the theory behind the design of a computer."
This is known as the use–mention distinction. For the vast majority of articles, the introduction is using a term ("Computer architecture is a theory"), rather than mentioning it.Great Schism may refer to either of two schisms in the history of Christianity: ...
When referring directly to a term rather than using it, write the word in italics, as shown above; see WP:WORDSASWORDS.
Write material that is true: check your facts. Do not write material that is false. This might require that you verify your alleged facts.
This is a crucial part of citing good sources: even if you think you know something, you have to provide references anyway to prove to the reader that the fact is true. Material that seems to naturally stem from sourced claims might not have been actually claimed. In searching for good references to cite, you might even learn something new.
Be careful about deleting material that may be factual. If you are inclined to delete something from an entry, first consider checking whether it is true. If material is apparently factual, in other words substantiated and cited, be extra careful about deleting. An encyclopedia is a collection of facts. If another editor provided a fact, there was probably a reason for it that should not be overlooked. Therefore, consider each fact provided as potentially precious. Is the context or overall presentation the issue? If the fact does not belong in one particular article, maybe it belongs in another.
Examine entries you have worked on subsequent to revision by others. Have facts been omitted or deleted? It may be the case that you failed to provide sufficient substantiation for the facts, or that the facts you incorporated may need a clearer relationship to the entry. Protect your facts, but also be sure that they are presented meaningfully.
The advice about factual articles also applies to articles on fiction subjects. Further considerations apply when writing about fictional topics because they are inherently not real. It is important to keep these articles verifiable and encyclopedic.
If you add fictional information, clearly distinguish fact and fiction. As with normal articles, establish context so that a reader unfamiliar with the subject can get an idea about the article's meaning without having to check several links. Instead of writing:Trillian is Arthur Dent's girlfriend. She was taken away from Earth by Zaphod when he met her at a party. She meets Dent while travelling with Zaphod.Trillian is a fictional character from Douglas Adams' radio, book and now film series The Hitchhiker's Guide to the Galaxy. In the first book, Trillian is introduced to the main character Arthur Dent on a spaceship. In her backstory, she was taken away from Earth when the space alien Zaphod Beeblebrox met her at a party.
Works of fiction are generally considered to "come alive" for their audience. They therefore exist in a kind of perpetual present, regardless of when the fictional action is supposed to take place relative to the reader's "now". Thus, generally you should write about fiction using the historical present tense, not the past tense. (See WP:Manual of Style § Verb tense and .) Examples:
Conversely, discussion of history is usually written in the past tense and thus "fictional history" may be presented in that way as well.Chroniclers claimed that Thalestris, queen of the Amazons, seduced Alexander the Great.
Articles about fictional topics should not read like book reports; instead, they should explain the topic's significance to the work. After reading the article, the reader should be able to understand why a character, place, or event was included in the fictional work.
Editors are generally discouraged from adding fictional information from sources that cannot be verified or are limited to a very small number of readers, such as fan fiction and online role-playing games. In the latter case, if you absolutely have to write about the subject, please be especially careful to cite your sources.
If the subject, say a character in a television show, is too limited to be given a full article, then integrate information about that character into a larger article. It is better to write a larger article about the television show or a fictional universe itself than to create all sorts of stubs about its characters that nobody can find.
The most readable articles contain no irrelevant (nor only loosely relevant) information. While writing an article, you might find yourself digressing into a side subject. If you are wandering off-topic, consider placing the additional information into a different article, where it will fit more closely with that topic. If you provide a link to the other article, readers who are interested in the side topic have the option of digging into it, but readers who are not interested will not be distracted by it. Due to the way in which Wikipedia has grown, many articles contain redundant passages of this kind. Please be bold in merging these passages.
Pay attention to spelling, particularly of new page names. Articles with good spelling and proper grammar can help encourage further contributions of well-formed content. Proper spelling of an article name will also make it easier for other authors to link their articles to your article. Sloppiness begets sloppiness, so always do your best.
Avoid peacock terms that show off the subject of the article without containing any real information. Similarly, avoid weasel words that offer an opinion without really backing it up, and which are really used to express a non-neutral point of view.
Believe in your subject. Let the facts speak for themselves. If your ice hockey player, canton, or species of beetle is worth the reader's time, it will come out through the facts. However, in some cases (for example, history of graphic design) using superlative adjectives (in the "... one of the most important figures in the history of ..." format) in the description may help readers with no previous knowledge about the subject to learn about the importance or generally perceived status of the subject discussed. Note that to use this type of superlative adjective format, the most reputable experts in the relevant field must support the claim.
Avoid blanket terms unless you have verified them. For example, this article states that of the 18 Montgomery Counties in the United States, most are named after Richard Montgomery. This is a blanket statement. It may very well be true, but is it reliable? In this instance, the editor had done the research to verify this. Without the research, the statement should not be made. It is always a good idea to describe the research done and sign it on the article's talk page.
If you wish to, or must refer to an opinion, first make sure someone who holds some standing in that subject gives it. A view on former American President Gerald Ford from Henry Kissinger is more interesting for the reader than one from your teacher from school. Then say who holds the opinion being given, preferably with a source or a quote for it. Compare the following:
Sometimes the way around using these terms is to replace the statements with the facts that back them up. Instead of:The New York Yankees have won 26 World Series championships—almost three times as many as any other team.
By sticking to concrete and factual information, we can avoid the need to give any opinion at all. Doing so also makes for writing that is much more interesting, for example:William Peckenridge, eighth Duke of Omnium (1642? – May 8, 1691) is widely considered to be one of the most important men to carry that title.William Peckenridge, eighth Duke of Omnium (1642? – May 8, 1691) was personal counselor to King James I, general in the Wars of the Roses, a chemist, bandleader, and the director of the secret society known as The League of Extraordinary Gentlemen. He expanded the title of Omnium to include protectorship of Guiana and right of revocation for civil-service appointments in India.
Show, don't tell. The first example simply tells the reader that William Peckenridge was important. The second example shows the reader why he was important.
When repeating established views, it may be easier to simply state: "Before Nicolaus Copernicus, most people thought the sun revolved round the earth", rather than sacrifice clarity with details and sources, particularly if the statement forms only a small part of your article. However, in general, everything should be sourced, whether within the text, with a footnote, or with a general reference.
Make omissions explicit when creating or editing an article. When writing an article, always aim for completeness. If for some reason you cannot cover a point that should be explained, make that omission explicit. You can do this either by leaving a note on the discussion page or by leaving HTML comments within the text and adding a notice to the bottom about the omissions. This has two purposes: it entices others to contribute, and it alerts non-experts that the article they are reading does not yet give the full story.