You just have to advertise your site. Don't be a jerk about it, like don't advertise it here, and don't spam it on forums or chat rooms, but just like, link to it in your signature on a forum and then be an active member. The best way to generate traffic is word of mouth though. You tell two friends, they tell two friends, etc... If you have an advertising budget, then go to some big time sites and rent some ad space. Also, hypothetically speaking, let's say your website is about a football team. Well go find a chat room about that football team, and when someone brings up something about the team, say, "Oh yeah, you can read more about that on my website: (insert url here)" just don't overdo it or people will get annoyed with you.