College and grades and that sort of thing....help!!!?

I graduated Summa *** laude from high school with a near 4.0 unweighted gpa. I know college is going to be harder and everything. How do I get outstanding grades in college? I am extremely worried. I want to graduate Summa *** laude (or at least Magna *** laude) with Phi Beta Kappa honors from college and that is all I really want. I want this more than anything else in the world. How do I get there? Please give me insightful answers.