The vast trove of empical data out there on activities like programming suggest that practice is main way people get better. There's also a sizeable anount of evidence saying ideal practice is a series of problems that increase in difficulty, a bit harder than before, and not insurmountable. Plus, learning techniques & observing examples from experienced professionals.

College isn't likely to teach you much programming skill at all. Now, programming practice + a college education in CompSci concepts can make for a programmer with more tools in the toolbox (taps head). It's not a substitute for repeated, informed practice of act itself.