Let’s say you’re a dietician. Friends are very likely to come to you to ask for your advice on weight loss. This is a highly competitive online market and one that beginners would struggle to break into. But friends may also ask your professional dietician’s opinion on what foods to avoid if they suffer from bloating, or which foods help to reduce acne. These areas are less competitive and can provide a different angle for a dietician to begin an affiliate marketing website.
Do I need to learn "black hat" SEO (aka shady Search Engine Optimization) to succeed at affiliate marketing?

To further understand affiliate programs, let's consider an example — Wirecutter.com, a New York Times company, is a website that lists product recommendations for shoppers. Wirecutter largely earns commission based on affiliate relationships with retailers.
Like any other marketing channel, affiliate marketing is something that can be optimized and something that should be growing steadily. For the best results, calculate individual affiliate conversion rates to determine the quality of traffic that each affiliate produces.