Onsite Optimization:

This refers to all optimization techniques that you have control over on your physical server/website. this is broken down into:

Site Structure, the architecture of your site.

Page Structure, how your template is layed out the format of the page.

Page Content, the actual visable readable content of the page

The Content Oxymoron:

Google loves Fresh new content as much as it loves old content.

What this means is that google weighs a site on how long it has been around. If a page has existed for 1 year then it most likely isn't a spam page but contains valuable information.

On the other hand if a site has not been updated in 1 year it may not be as valuable a source of information as a site that is updated everyday.

So you need good quality long term content and also nice fresh weekly or daily content (often creating a blog can provide this for you)