No matter how good your marketing skills are, you’ll make less money on a bad product than you will on a valuable one. Take the time to study the demand for a product before promoting it. Make sure to research the seller with care before teaming up. Your time is worth a lot, and you want to be sure you’re spending it on a product that is profitable and a seller you can believe in.
Analytics are limited. Unlike with conversions made directly on your WordPress site, you’ll be limited in terms of what you can learn about the people making purchases through your affiliate links. While Amazon does provide you with details about clicks and sales, you won’t get deep insights into who the consumer was and what they did on your site before they got to that point that you would with Google Analytics.