If you are new to SEO, a good place to start is right at Google. Since it is Google’s search engine algorithm that serves up most of the world’s online searches, Google is the primary search engine given consideration for most SEO work. If your site is optimized for Google, then your work is pretty much done, at least for on-site SEO. The work of off-site SEO is never done, since it can always be better.
Gain a solid understanding of the fundamentals first and get started in the right direction:
This is a link to the Search Engine Optimization Starter Guide (PDF) published by Google Inc.