I switched from 3D game development to 2D, and I want to make 2D images for my games. I'm aiming to be a "lone wolf" meaning I make my games by myself, and I have all the skills to do so. Even though I am not artistic by heart, I'd like to learn.
That leads me to two questions:
1. What software should I use?
2. Where should I learn how to use that software effectively?