Even though these are two different methods, marketing experts have started to combine them in order to maximize the results. Here is how you can use them to your advantage too: Find influencers and established bloggers in your niche and reach out to them directly (via email, or direct message on social media). However, it’s important to build a relationship before pitching your affiliate program.
When it comes to Facebook, it’s best to join groups where your target affiliates are active. The groups you’re looking for are either product-centric or affiliate-centric groups. Once you find people you want to recruit, approach them with a purpose to build a relationship before letting them know about your affiliate program.

In terms of how to start affiliate marketing with email, all you have to do to promote an affiliate product is send an email to your list… Some people will open your email. Of those, some click on your affiliate link. And, of those, some will buy the product!
If you have done your due diligence on your chosen niche, you will get a clearer picture of how your selected niche will perform. You can then use this information to create a realistic target. Typically, a niche with too many competitors and very minimal demand doesn't bud well.