The challenges I think one might face in this affiliate marketing job is usually in the early stages where you will get to encounter stuffs that are quite related to money and efforts, you should better that it is a complicated job to try to convince people into buying a product you do not really know much about, you will have to learn about it first, at least somethings about it which will help you more when you are marketing it to your clients so they will find a reason to buy from you, and I heard one has to also put in some money in some sites