You don't need programming skills to be a successful affiliate, but it certainly can help. Programming can not only help your affiliate projects, but broaden your skill-set to expand your business.
Here are some resources to help you get started programming. There are thousands to choose from, but these are a good start. I'm not an expert programmer myself by any means, so I refer to these resources often. From an affiliate perspective (and arguably overall) the best language to learn would be PHP.
You'll need a basic HTML editor
Depending on what you're doing, you may need an editor like
For motivation, here are a few good reads
Even if you don't want to be a developer, it will help any type of online business you do to have a basic concept of coding. Even if you outsource your coding, learning about it will help you know if an outsourced programmer is doing a good job and charging a fair price.