Recently an artist ask me how I can paint works in so many types of mediums. As you may already know I try to help other artists to achieve their own goals so I try to answer all the questions that are asked. But this question is a bit difficult for me to answer. But I will attempt to give a reasonable answer to the question. Hope it helps.
I am a driven artist, I can't seem to go a day without doing some sort of art, even if only for a few minutes. There was a time when I would never be without my sketch pad. I still carry one most of the time. I also become bored with the art I am doing easily so I change mediums often.
I can remember years ago that I would never turn a commission down even if I had never used a medium they wanted or a style they wanted. So I would spend time in the library studying that particular medium or style then paint with that medium and style till I could do it intuitively. Everything always involved lots of practice for me. I threw away so much art you would not believe because I was always practicing. Everyone needs to practice their style till it becomes second nature. It doesn't matter how long it takes you, it will improve your art. I suppose it is because I was so determined to learn that I am where I am today with my art. I am constantly evolving and learning.
It is so much easier now with computers to study and even take classes. I never did the class thing, just books from the library helped me learn the basics so I could take it further. So get busy practicing, paint, draw, write, etc...