I would suggest studying problem-solving in general. There's the book How to Solve It, by George Polya, that I'd highly recommend. You could also check out How to Solve It: Modern Heuristics, by Michalewicz and Fogel. Both are very fun and informative.
You might also check out the application questions in your calculus book. These tend to be end-of-the-chapter questions that bring a lot of different topics together.
All of this will help get your thinking to be more creative and imaginative. Because really, the most important quality a mathematician can possess (or anyone desiring to be good at math) is a good imagination. So you need to train your imagination. That means reading good books. I don't mean the latest junk, I mean classics like Homer, Virgil, Dante, Milton, Austen, Dickens, Tolstoy, and Tolkein. Take a look here for a good start. Training your imagination also means cutting down drastically on video games and TV (both regular TV and movies).
You can train yourself to be better. I'm just saying I think it'll take a while, and a lot of hard work.