I'm sorry for such a late reply! Thank you, I'm really glad that you like it!
Most of what I learned I learned from "How To"s and Coloring Tutorials on deviantart. They can be really helpful. After learning basics from those a lot of it is trial and error and developing your own style and ways of doing things. One big thing that I felt helpful is using as many layers as you need to make yourself feel comfortable. Then sort your layers into folders for different parts of the picture to keep track of them. If you separate things into layers they can be easier to fix later, and then the more you learn and develop your skills the less layers you will need.
I hope that helps a little. I really suggest looking at tutorials on deviantart, there are a lot of fantastic ones.