I think Search engine optimization can help you with that..You can also write unique articles for your blog, directory submission, forum posting and blog commenting can do wonders too
By optimizing your site for search engine. Proper keyword placement, rich keyword content, good coding avoid flash, build quality backlinks using every possible techniques. Try to get few accounts on social networking sites like Twitter, facebook, myspace and linkedin.com . These sites will surely help you to increase your website traffic. For building quality backlinks submit your quality articles to top article directories as well as submit your site to web directories and rss feed directories.
If you don't want to spend your valuable time on doing SEO activities, the you may opt for PPC campaigns. This is also one of the best way to increase sales and traffic of your website.