Getting your products ranked well on Amazon is a completely different world from getting your web pages ranked in Google. Amazon SEO isn't something I do, but many of my clients ask about it. DesignRush has put together a guide on how to optimize your product listings on Amazon.
They do a great job of explaining how search works on Amazon (it's MUCH different than Google search; I'd actually say Amazon search unfortunately is nowhere near as good, and I often find myself exiting Amazon.com and doing a Google search to find what I'm looking for on Amazon).
Amazon has a score known as sales rank, and the article above explains that as well. Then, they cover their 5 favorite tools for optimizing on Amazon.com.
