Converting visitors to cash with Amazon

I have a few sites ranking for some buying keywords and the amount of conversions versus the amount of traffic is far below what I want it to be. Lots of you guys seem to be breezing by with Amazon but I obviously don't have the right formula or something because the traffic is there and it's very targeted.

My current strategy is building a site around a shopping niche and then I make categories for each sub niche which has any significant search traffic. Then in each of those categories I add posts by picking related products and making a review about that product with my affiliate link in it. I'm doing 1 product in each post, writing a short review / description for the product and then placing a "buy from amazon" button with my link attached.

Am I doing this wrong or something? All feedback is appreciated.