The first principle to understand in designing your site is that you don't optimize your whole site all at once. You're optimizing each and every page of your site individually. Many people think they only need to optimize their home page and then they're done. Many times when you click on a link from a search engine results page, it will take you to a specific page on your site. Thus, SEO is a very time-consuming and tedious ongoing process that needs to be carefully thought out and executed. (Search Engine Watch)
From an article by Ron Jones for Search Engine Watch Dec 22 2008.
Links
Search Engine Watch website
SEO Site Structure 101