I do try to be as mindful as possible of the world the characters come from when I draw fan art. Or any art, I guess. I hardly ever do straight-up portraits because I always want to show something of the surroundings as well.
We'll all be learning until the day we die - humans are such curious creatures after all. You're pretty well advanced in my opinion and im sure you'll be super fabulous amazing at art if you keep this up. In the meantime I think I'll put my pencil down and admit defeat. Anyhow keep it up Lex!