I’ve been an editor at Dmoz for years. Over that time I’ve heard more than my fair share of complaints about how hard it is to get a website listed. The single best tip I can give you is this:
Make sure you submit to the right category and comply with the Title and Description requirements! 99.9% of sites I review need to be moved to the right category and have their Title and Descriptions re-written to comply with the rules. If there’s lots of sites to edit you can imagine how time consuming this will be.
Don’t make it hard for the editors. You’ll find your site gets approved far quicker if the only thing an editor needs to do is hit the “approve” button.