I wonder how to drive quality traffic to my own Amazon store. I have a feeling that most people that want to buy products from Amazon go directly to Amazon website itself and buy them. How many visitors do you feel are reaching the websites of Amazon affiliates to purchase products? Are they large in number or very few? Hence the best way to earn from amazon affiliate program is by referring customers to them. Cookie period of course helps us a great deal. Repeat buyers could be rare with Amazon program I believe. Am I wrong?
You have to offer something that Amazon don't offer. Unique articles, reviews of the products, comparisons of the products etc. Think about ways that you can offer value via your store which makes customers want to use it instead of going direct to Amazon.
Better to add the Amazon ads to your webpages. The stores are not very user friendly and don't encourage browsing to other products.
Build better content. You can make comparisons, reviews, provide more information than people get at vendor's store. Also you can edge out your pages around individual keywords and create more relevant content for them. You will have lower volumes of traffic but it will be targeted, people will come to your site through search engines searching exactly about your topic.