How to spice up a school uniform?

I have to wear uniform for 1 more year! Yes!!! I want to look fresh this year. I have to wear polos (any color, but no logos) khaki, navy or black twill pants (they are not aloud to be skinnys, stupid school :/) with a belt, and no purses! Ugh :/ We can have accessory's though, thank god! We cant have crazy hair styles... :[ So I need somthing calm and not to out there.