I have had great results by writing 2 or three 500 word articles on specific pages in my site and including two to three links in each article.
Then I blast the article to every article site I can find and within 2 weeks I'll bae 50 to 60 backlinks and a pretty good
PR.
Google loves backlinks and they help alot with other serach engines.
Of course, you have to do all the little stuff first: meta tags, keyword rich content, revelent to keywords in the url, keywords in the image tags (don't spam though)
And this system works very well for me.