I think that this is most important, good posts with some long tail keywords to make the search engine happy.......... post often so that the spiders return frequently.
There are 8 good way for On-Page.. Page Titles, Meta Descriptions, Meta Tags, URL Structure, Body Tags (H1, H2, H3, H4, etc.), Keyword Density, Image SEO, Internal Linking
Key point to consider in a post-pandguin world:- don't make Google work. If you create good, original content, and make it easy for Google to spider it, you will get rewarded. If you make Google work, you will get punished. Keyword stuffing, over linking, things like this make Google do extra work to try and figure out if you're a spammer or not, and frankly, it costs them money. You keep it whitehat, the 'on page optimization' will pretty much take care of itself.
Maintain your pages and pages contents with proper keyword density, keyword proximity and keyword prominence, maintaining your URL structure Proper with targeting keywords.