Affiliate marketing currently lacks industry standards for training and certification. There are some training courses and seminars that result in certifications; however, the acceptance of such certifications is mostly due to the reputation of the individual or company issuing the certification. Affiliate marketing is not commonly taught in universities, and only a few college instructors work with Internet marketers to introduce the subject to students majoring in marketing.
1) Gross Profit Margin – This is the first place I start. Clearly you can't offer 50% commissions on items that you only have a 20% profit margin or you'd be out of business fast (and probably in debt). So start by determining your minimum, median, and average gross profit margins on items in your store. You may also want to determine these numbers separately for each category or product type since it's possible to offer different commission rates for each product category, depending on how complex you'd like to make your program. In my experience, the simpler the better when it comes to commission structure, but technically anything's possible.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.