Take the email below from Paperless Post, for example. I love the header of this email: It provides a clear CTA that includes a sense of urgency. Then, the subheader asks a question that forces recipients to think to themselves, "Wait, when is Mother's Day again? Did I buy Mom a card?" Below this copy, the simple grid design is both easy to scan and quite visually appealing. Each card picture is a CTA in and of itself -- click on any one of them, and you'll be taken to a purchase page.
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.