Hey guys, what can I do to improve the SEO on my wordpress site.

How can I optimize it for a key term?

Where should i use the heading tags on my theme? I generally do this:

h1 - main header w/ site url
h2 - post titles
h3 - sidebar headings
ul/li's - sidebar/navigation

Not sure if thats the best way to do it I think I read online you should use h1's for post titles?

Any other tips would be appreciated. I had a quick look though google and all the top sites on it seemed to be really old.

Thanks......