Despite back linking and off page optimization far outweighing the power of on-page optimization, it should still have a relevant part to play in your SEO plans. Although you can never get high rankings for competitive keywords by just on-page optimization, by following the basics you can achieve good rankings for hundreds of long tail keywords on a single site.
I often attach a blog to any website I create because I have found that I can use it to target long tail keywords as and when required.
So what on page optimization should you focus on? Here are three areas on your site which have the greatest affect on your rankings: