Commenting on blog posts written by industry experts with lots of followers can bring your website a lot of traffic. When you post a comment (most) blogs allow you to leave a link back to your site for other readers to check out – as long as you leave an insightful comment you WILL get traffic from your blog comments. Make sure you comment as quickly as possible when new blog posts go up. The higher in the comments you are the more clicks you’ll get. I have Google Reader setup to alert me when new blog posts are made on the industry blogs I follow and I comment immediately to lock in my first place spot.
Do not be fooled by those traffic sellers promising thousands of hits an hour. What they really do is load up your URL in a program, along with a list of proxies. Then they run the program for a few hours. It looks like someone is on your site because your logs show visitors from thousands of different IPs. What happens in reality is your website is just pinged by the proxy, no one really sees your site. It is a waste of money.