There isn’t a ‘one size fits all’ SEO solution either. eCommerce sites are so very varied. There are many eCommerce site platforms and each of those platforms is often tailored somewhat per the customer needs.
When thinking about ecommerce search engine optimization you need to pick a person/company who is familiar with the different platforms and the programming involved in them.
I came across Search-Placement.com, a company that can take care of your eCommerce SEO for you without it costing you an arm, a leg or your soul.
Their site is full of what you need to know about SEO, they even offer a free site analysis and a monthly newsletter.
Take a look [here]