Generally, you need search engine marketing help. SEM involves a number of activities:
1. optimizing your website keywords - in the meta tags and body copy. you should check keyword checker tools to see which keywords have good response rates. then setup your keywords in your meta tags and body copy.
2. start a link campaign - get as many incoming links as you can. post on forums like this one, and include your website URL in your post. (search engine spiders love forums). why didn't you do that here?!

submit your site to industry-related directories. there are lots of paid directories depending on your particular industry.
3. get news coverage, with online articles pointing to your website.
4. start PPC (pay per click) ad campaigns - Google Adwords, Yahoo's Overture, Microsoft AdCenter, and Business.com are good ones to start with.
5. Monitor your traffic statistics and page rank. pay attention to to success of your keywords, and referring links.
6. Based on #5, optimize and refine steps 1-4
7. Repeat.
Or hire a SEM specialist. They're experts in these steps.