I'm currently a marketing major in college. I'm want to get started in Internet marketing, SEO, and SEM. I've been reading everything I can of those subjects, plus google analytic.
Search Engine Optimization (SEO) now-a-days covers quite a range of items that your website will need.
First of all there is no single item that will do the trick. Its a combination of of various pieces to the puzzle. Part of it lies within your website and the other part you can call an "outreach" program by getting your links onto other websites (e.g. blogs, social bookmarks, forums, press releases, etc)
Outside of that you also are missing a DocType in your HTML code. Take a look here:
http://www.w3.org/QA/2002/04/valid-dtd-list.html
While you're at the W3C take a look at your validation errors too:
http://validator.w3.org/
We have an article that we wrote you can read here:
http://www.smartfindsmarketing.com/articles.php?p=articles_define_marketing
Also, touch base with Webmaster forums for more information like the following three:
http://forums.digitalpoint.com/
http://www.v7n.com/forums/
http://www.warriorforum.com/forum/
Also, here is another good resource:
http://www.seochat.com
One last thing. You will need to get into the process of generator a sitemap of your website regularly as a sitemap.xml file. You can read more about this at http://www.sitemaps.org created by Google, Yahoo and MSN and you will need a sitemap generator at http://www.smartfindsmarketing.com/xml_sitemaps.php You can then submit your sitemaps to the search engines in their respective areas.
Learn about Link Popularity, Google Page Rank, Alexa Traffic Rank, Keyword Density
Hope this helps