This is something that any good web developer should know about. One of the best ways to get traffic to your website is through search engines such as Google and Bing. Websites are ranked according to how relevant they are perceived to be based on the quantity and quality of outside links that point to that site. Search engines will regularly visit your site and record the content to use in their search process. I use semantic mark up on all content to make it as accessible to search engines as possible. Keywords in the site content are important to help people find your site. Identify a set of relevant words that people may use when searching, I will add them to the search engine's keywords list. I do not recommend a conceited effort to pepper your content with keywords - while this may raise traffic it is likely to turn visitors off. The overall goal is conversion of visitors to customers, and that requires the personal touch.
The marketing side of things is really down to you as your website is your project. As a web developer I can aid you in the process by:
You may want to post in some relevant newsgroups/blogs, preferably answering some questions. You can aid the marketing process with any publicity you can get for your website.