The first thing that you want to do is to perform an affiliate program competitive analysis to research and find out what your direct competitors are offering. This is important as affiliates will compare you against others in your industry and may opt to promote someone else if their payouts are higher. You do want your competitive payouts to stand out.
According to HowStuffWorks, “Affiliate programs, also called associate programs, are arrangements in which an online merchant website pays affiliate websites a commission to send it traffic. These affiliate websites post links to the merchant site and are paid according to a particular agreement. This agreement is usually based on the number of people the affiliate sends to the merchant's site or the number of people they send who buy something or perform some other action.
It’s also important to research their payout structure. Not all payouts are the same and tier affiliate marketing often offer different payouts. Some might pay you on the first offer but pay you nothing on any upsells. Ideally, you should be paid for every transaction. In doing your research, you’ll find out which affiliate payout structures are the most profitable.