"WP:NOTYOU" redirects here. For the policy on avoiding personal attacks, see WP:AVOIDYOU. For the use of second-person pronouns in Wikipedia articles, see WP:YOU.
Essay on editing Wikipedia
Wikipedia is not the place to write about yourself or your personal projects
While we're happy that you have chosen to contribute to Wikipedia, you need to remember... Wikipedia is not about you.
Sure, you see Wikipedia articles on all sorts of individuals, films, companies, projects, etc., but it is strongly urged that those articles not be written by involved persons. Yes, it can be tempting to write about yourself or projects in which you have a strong personal involvement, and perhaps you might feel your personal knowledge uniquely qualifies you on the subject, but that involvement and that personal knowledge reflect a conflict of interest. That you might "know" something is fine, but for inclusion in Wikipedia, we require confirmation that the world at large already knows about it too.
Cautions
Don't write about yourself, your friends, your website, your company, your business, your family, a band you're in, your teacher, a word you made up, a story you wrote, your hamster, or anything else you're closely affiliated with. If the subject is too close to you, it falls under scrutiny as a conflict of interest. If your username is Big Blast and you write about Big Blast, the musician, or Big Blast the Demolition Company, or Big Blast Pancakes, you'll catch the immediate eye of editors whose chosen task is to investigate and curtail conflict of interest or blatant advertising, which is contrary to the purpose of Wikipedia.
If "Big Blast", the musician, or "Big Blast Pancakes" are worth writing about, you should wait until someone else writes it. If Big Blast is actually not you, then perhaps starting with a different username will prevent the appearance that it is. Conflict of interest is a big deal on Wikipedia, as Wikipedia strongly discourages any attempt at self-promotion. So choose something else that interests you and that will itself be of interest to others.