Applying for New Categories: Advice and Guidance - Official guidelines on getting higher and more diverse editing privileges. Also includes a basic overview of the "do's" and "don'ts" of editing.
There's More to Editing than Unreviewed - Site submissions is only one of the many ways for you to get sites to add to your category. Here are a few other ways you can find quality sites to add to your categories.
Title Examples - Offers advice and provides examples of good vs. bad titles.
Verb Choice Thread - Provides information on verbs in the context of Web site description writing.