Ok so my photo teacher is the funniest. She totally kicks you in the butt and tells you if you take a bad photo. She'll let you know to your face in front of the class. That is, I think, one of the best ways to become good--have a teacher that's hard but fun at the same time. I can tell already that I'm going to be getting better at photography.
If you get a chance, take an art course in college it's totally way better than high school.