Good luck! I looked it over and have some suggestions if you don't mind.
- Each of the forums has a totally different design. If you can, it's best to choose one design for the entire forum. Otherwise, it just makes things confusing.
- You need to have something somewhere explaining what the site is all about. For phpBB forums, the about page is usually a topic page in the first listed forum.
- You might want to get rid of the forum images. I experimented with those somewhat long ago on a temporary YWS board, and people didn't like them.
Best of luck, and just keep working at it. I've been trying to get another writing site, The Writers Society, going for well over a year and it's just now succeeding.
Edit
Another good thing to do with advertising a new site is to emphasize how small it is. When I started YWS, I told people that you were guaranteed to get reviewed and be noticed at YWS then at the much larger sites.