My forum is a mostly anime forum with adsense rev sharing, aand I was wondering how I would go about SEOing it. The forum: http://www.mostlyanimefun.com/index.php
get some keyword analysis with help of keyword tools.....................and analyze your competitor sites ...........then post it to directory, article, social bookmarking, press release, blogs, and forums.................
Get quality related backlinks try blog post and forum postings on related websites like yours. Also do it manually google doesnt like it auto they are picky now a days. And rember never to give up i do about a 50-100 a day it just takes time.
For ideas on on-page and on-site SEO techniques, check out this forum and others like webmasterworld.com. For off-site SEO, you're going to need backlinks from relevant sites so that you can drive targeted traffic to your site. I would suggest dropping links on other anime forums, blogs, etc. as well as possibly submitting articles to ezinearticles.com and other article submission sites about anime. On-page/on-site SEO is the easy part. Getting the word out that your site exists and building a community is the hard part.