Google will black list sites that cheat. I found that out the hard way. I had a site that had half a dozen good listings in google by cheating hidden div tags and a PR of 5. After a few months, it suddenly dropped off google all together. Nothing, no PR, no listings, notta. If your site is/was blacklisted, you can email them when you clean it up and they will remove the blacklisting.
I try to stay up on SEO tips, but make no self-proclaim of being an expert. Having said that, you are welcome to download my index.html page in my signature and study it. I have a number one rank for Amarillo Web Design on several search engines, including google.com.
Proper use of Title, meta tags (though I hear google ignores meta tags, but I'm not convinced of that), H1, H2, H3 tags and bolding keywords AFTER the first paragraph help. Assigning your keywords to image titles/alt text, assigning keyword to your .css file name (keyword.css).