First, embark on a solid article marketing strategy by writing unique high-value articles about your site topic and submitting those articles to other sites, ezines, etc. Do this on a regular, consistent basis. Have a resource box at the bottom of each article that contains your site's URL.
Then embark on a link building strategy to get other quality sites to link to your site.
Doing so will generate targeted traffic directly from all the inbound links AND improve your search engine ranking (which will also bring in more traffic).
Once you have the traffic, be sure to have profitable sales copy to convert the traffic to paying customers.
Of course, underlying all of this is the assumption that you have a product (or products) that your target market actually wants and will pay for. If you're trying to sell a product nobody wants, all the traffic in the world won't do anybody any good!