Do a bit of reasearch on google, msn, yahoo for the most popular searches. Take a look at what others are searching for then develope content around those things. Update your sitemaps, keywords, and page descriptions.
If you are dedicated to a certain TYPE of site or subject, find forums and blogs that concern that subject and make meaningful posts there. Include your URL in your signature.
Once traffic starts to build, think about placing a forum package on your site. Net users like to have places where they can offer an opinion or advice then come back and check the replies.
Starting your own blog and syndicating the RSS feed is another way to get your site more exposure.
And, as you already know, place your URL everywhere you can! I got lots of room for more links at my search engine!
Al