Read this article from SEO for Blogs.

“When thinking about search engine optimization and where to begin, think about on-page optimization. Although off-page optimization is essential for improving your Google rankings, on-page techniques can be used to build a strong SEO foundation and support good results on Yahoo!, MSN, and other major search portals.

Here are a number of on page optimization tips and strategies you can apply immediately to enhance your website and make is truly search engine friendly. As search engines crawl your website, they can apply the proper weight to different content.”