Write Articles
Post interesting and useful articles to article directories, and make sure each article entices the reader to visit your site. People will come read what you wrote, and if they like it - they will go to your site to learn more.
Join the Blogosphere
Blogging is a great way to get people to read what you you have to say. Blog about the topic of your site. Make sure that each time you post something, you let others know about it by pinging your post. And don't just stay within your blog, go visit other blogs and comment on them. If you join the discussions on other blogs, others will come join yours.
Paid advertising
You can pay for visitors to come to your site. Either place banners on other sites, or buy ads on the search engines. You may be required to pay per impression (person who sees your ad) or per click (person who clicks on your ad and goes to your site).
Social media
Create a following for yourself in the social media by joining in other people's conversations and creating your own. People will want to read what you have to say, and will visit your site for more information.
Offline advertising
You don't have to limit yourself to online advertising. Use flyers, business cards, classified ads, and other conventional techniques to advertise your website's address. Give people a compelling reason to come to your site and they will do so.
Each one of these techniques requires some learning, but they are all very useful when it comes to getting people to visit your site. Start with one technique, and as you master it go on to the next one. Before you know it you will be getting lots of traffic to your site.