How to improve class rank?

Your class rank depends not only on your grades but on the grades of every one of those 580 members of your class. And most of them are thinking 'how can I raise my class rank'. No, you probably can't raise it significantly at this point, and no one can tell you how much you can raise it except maybe your guidance counselor, who is the only person with access to everyone's GPA. If you got all A's this year and took the same number of credits each year, you'd graduate with a (3.2 * 3 + 4.0 * 1) / 4 = 3.4 GPA. 6 weeks worth of good grades won't do much of anything even if there is a quarter at the end of that where GPA is recalculated. Colleges ask for unweighted GPA.