The number and quality of links pointing to your site is one of the major factors that influence the position of your web site in the search engines. Ideally you want to be on the first page for your main keyword phrase to receive the most traffic. 

One thing you can do to generate lots of quality backlinks to your web site by writing quality articles that includes your keyword phrase in the content and a live link pointing back to your site in the resource box at the end of the article. 

You should carefully monitor your results by periodically checking your rankings and site stats.  Some article directories provide stats on a control panel telling you how many people have read your articles.