I've been wanting to write something similar for a long time. I left high school feeling very "bad at math", and now I'm a CS major with a math minor.
I think the biggest problem in my approach to learning was my refusal to practice. From other classes, I was used to reading the textbook and understanding immediately. That meant to study for math exams, I would read the chapters, try to learn principles, and memorize some formulas.
I later realized that I would never get any better without doing practice problems - and lots of them. The best advice I've gotten is to start with the problem, and then learn.
I find this more difficult to do as I progress. My calculus book was full of difficult example problems so that I was prepared to tackle the problem sets whereas my number theory book has some proofs and trivial examples, leaving me almost completely unprepared for the problem sets without hours and hours of struggle.
I think the biggest problem in my approach to learning was my refusal to practice. From other classes, I was used to reading the textbook and understanding immediately. That meant to study for math exams, I would read the chapters, try to learn principles, and memorize some formulas.
I later realized that I would never get any better without doing practice problems - and lots of them. The best advice I've gotten is to start with the problem, and then learn.