It may seem a bit silly to discuss the Editing policy of the "encyclopedia anyone can edit" but openness isn't quite the same thing as anarchy. Here are some concepts to keep in mind:
Wikipedia doesn't have to be perfect… but it should be presentable. It's OK to leave a subject incomplete—and what does "complete" mean, anyway?—but do finish your sentences.
Add a "citation needed" tag if you really must, but avoid making more work for others. If you see something wrong, try first to fix it, and then leave a note for someone else to try later.
Follow all policies and guidelines! Did I really have to say that? Yeah, it never hurts.