Although I have never done much affiliate marketing, Peters's AFFILIATE MARKETING FOR BEGINNERS seems to me to be an excellent introduction. It surprised me that a lot of the material presented was useful for making money online in other ways than affiliate marketing. For example, there are recommendations concerning outsourcing content, on- and off-page search engine optimization, and press releases. I am not unfamiliar with such topics, and the recommendations seem very good. The whole book is clearly organized and well-written. There is even a bonus e-book provided at its end. This book is an outstanding value.
There are two ways to approach affiliate marketing: You can offer an affiliate program to others or you can sign up to be another business's affiliate. As the business driving an affiliate program, you'll pay your affiliates a commission fee for every lead or sale they drive to your website. Your main goal should be to find affiliates who'll reach untapped markets. For example, a company with an e-zine may make a good affiliate because its subscribers are hungry for resources. So introducing your offer through a "trusted" company can grab the attention of prospects you might not have otherwise reached.