I'd like to share a post that I found recently from a product's blog called LiftSuggest. It is focused on recommender engines for e-commerces and give several tips about how to design your product recommender at your website for maximum clicks and to increase your sales.
They posted a infographic about the anatomy of a product recommender engine. The tips they give are quite important when you are designing a recommender system for your e-commerce.
|Product Recommender Engine|
Further information please access their blog.