1. Understand what source of traffic you are interested in
2. Look for real cases with this source of traffic, understand the types of providers and niches
3. Choose a niche, read cases from the source + niches
4. Find a CPA network that you are going to promote. Look for reviews and reputation,
5. Start traffic, lose the first money, realize what to fix and start earning.
Really the advice is simple, start doing something and then you'll realize along the way what you need to learn and what to work on. The hardest part is getting started