First you have to know a bit about Affiliate marketing and realize that actually there are at least very different types of affiliates and they all serve different purposes in the sales cycle. Some help push value conscious consumers over the edge (ie, coupon based sites that you refer to), but others drive a totally different purpose.. They are more upper funnel (Loyalty, Content, Non-Profit publishers). I could help you create a plan and policies to effectively navigate the affiliate space. Good luck :)