I was in the IB program during highschool and found that that was much harder than my first year of university.
Studying practices are always different between people. I know some people like to study every night, keep current with lectures and all that, but I found I did fine with just going lectures, listening and then studying hard 1-2 weeks before a test, 2-3 weeks before an exam depending on the course.
Also, as others said, don't buy the textbooks early. For some annoying reason, professors will mark a book as required, and then on the first day of class will say "It's not really required, more of a study aid, all you need to know are in these handouts/notes, etc.".
I never bothered to resell any of my books, as I find they look nice on a bookshelf and they become somewhat useful when having to write lab reports/essays.
You know you can return textbooks right....