Opinion polls are great for generating data to publish at a later date, and also to add some interactivity to your site. Publish an e-mail newsletter on a regular schedule that informs subscribers about updates to your site, new about the topic of your site and pretty much anything you care to write about from month to month. Word of mouth is a very effective method to market your site. If you're not utilizing this tactic yet, you should be. Every page on your site should have a link where visitors can click to tell a friend about your great site.
Testimonials are very persuasive and effective.
If they're not telling you, just ask them. Add a short survey to you site and solicit comments. Be sure to get their permission and publish the flattering remarks on your site. If you have a flair for writing, or even if you don't, do some research and author articles and reviews that pertain to the focus of your site. Jam Okay, you've created a great site, but nobody is coming to visit.