This looks like a good article on search optimization. It’s stuff you’ve heard again and again. I thought the best parts were to avoid search engine firms that promise the world. Like top placement and saying it’ll be easy.
The best advice though? Stop worrying about your search rankings and try to improve your conversion rate. How many customers come to your web site and can’t find what they need? Or, does your product description answer the questions people typically have? Can it be better?