The reality in affiliate marketing is that it's like most other work-at-home ventures; there are a few who are filthy rich, a good number who are successful enough to meet their goals, and a ton who aren't making anything. So, the question isn't really whether or not affiliate marketing is a viable income option (it is), but whether or not you can make affiliate marketing work for you. Only you can decide that. But to help, here are some tips.
Affiliate marketing is also called "performance marketing", in reference to how sales employees are typically being compensated. Such employees are typically paid a commission for each sale they close, and sometimes are paid performance incentives for exceeding objectives. Affiliates are not employed by the advertiser whose products or services they promote, but the compensation models applied to affiliate marketing are very similar to the ones used for people in the advertisers' internal sales department.