One of Wikipedia's rules to consider:

Please make omissions explicit when creating or editing an article. When writing an article, always aim for completeness. But if for some reason you can't cover a point that should be covered, 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're reading doesn't yet give the full story.

Don't feel bad if you can't rigorously cover every aspect of some subject. That's why Wikipedia is a collaborative encyclopedia—we work together to achieve what we could not achieve individually. Every aspect that you cover means less work for someone else, plus you may cover something that someone else may not think of, but is nevertheless important to the subject.

List of undone stuff

If you note omissions by linking to to be written, then such pages will show up in this list (http://en2.wikipedia.org/w/wiki.phtml?title=Special:Whatlinkshere&target=To+be+written), and people clicking the link will get this explanation. Maybe that's useful. This recommendation was hardly practised as of February 2004, and is being replaced by...

To-do lists

Add {{todo}} to the top of the talk page of articles for which you can establish some goals, priorities or things to do.

Always leave something undone

The following rule was historically used to help challenge people's preconceptions of what an encyclopedia should be. While in practice it's not something we recommend, it makes for an interesting debating point.

Whenever you write a page, never finish it. Always leave something obvious to do: an uncompleted sentence, a question in the text (with a not-too-obscure answer someone can supply), wikied links that are of interest, requests for help from specific other Wikipedians, the beginning of a provocative argument that someone simply must fill in, etc. The purpose of this rule is to encourage others to keep working on the wiki.

The counter-argument is that people need no encouragement to edit articles. They should even think more before editing. Leaving things so that they deliberately seem unfinished just makes the project look amateurish. Articles should, as much as possible, be usable and coherent as a whole despite the fact that they will later be expanded. To-do lists should be used to point people in the right direction regarding future edits.

See also: Contribute what you know or are willing to learn more about — the two suggestions complement each other