Wikipedia:Your first article | things to avoid

Things to avoid

Articles about yourself, your family or friends, your website, a band you're in, your teacher, a word you made up, or a story you wrote 
If you are worthy of inclusion in the encyclopedia, let someone else add an article for you. Putting your friends in an encyclopedia may seem like a nice surprise or an amusing joke, but articles like this are likely to be removed. In this process, feelings may be hurt and you may be blocked from editing if you repeatedly make attempts to re-create the article. These things can be avoided by a little forethought on your part. The article may remain if you have enough humility to make it neutral and you really are notable, but even then it's best to submit a draft for approval and consensus of the community instead of just posting it up, since unconscious biases may still exist of which you may not be aware.
Advertising 
Please do not try to promote your product or business. Please do not insert external links to your commercial website unless a neutral party would judge that the link truly belongs in the article; we do have articles about products like Kleenex or Sharpies, or notable businesses such as McDonald's, but if you are writing about a product or business be sure you write from a neutral point of view, that you have no conflict of interest, and that you are able to find references in reliable sources that are independent from the subject you are writing about.
Attacks on a person or organization 
Material that violates our biographies of living persons policy or is intended to threaten, defame, or harass its subject or another entity is not permitted. Unsourced negative information, especially in articles about living people, is quickly removed, and attack pages may be deleted immediately.
Personal essays or original research 
Wikipedia surveys existing human knowledge; it is not a place to publish new work. Do not write articles that present your own original theories, opinions, or insights, even if you can support them by reference to accepted work. A common mistake is to present a novel synthesis of ideas in an article. Remember, just because both Fact A and Fact B are true does not mean that A caused B, or vice versa ( fallacies). If the synthesis or causation is true, locate and cite reliable sources that report the connection.
Non-notable topics 
People frequently add pages to Wikipedia without considering whether the topic is really notable enough to go into an encyclopedia. Because Wikipedia does not have the space limitations of paper-based encyclopedias, our notability policies and guidelines allow a wide range of articles – however, they do not allow every topic to be included. A particularly common special case of this is pages about people, companies, or groups of people, that do not substantiate the notability or importance of their subject with reliable sources, so we have decided that such pages may be speedily deleted under our WP:SPEEDY policy. This can offend – so please consider whether your chosen topic is notable enough for Wikipedia, and then substantiate the notability or importance of your subject by citing those reliable sources in the process of creating your article. Wikipedia is not a directory of everything in existence.
A single sentence or only a website link
Articles need to have real content of their own.
See also:
Other Languages
Chavacano de Zamboanga: Ayuda:Tu primer artículo
беларуская (тарашкевіца)‎: Вікіпэдыя:Як стварыць новы артыкул