How do you accessorize a uniform?

So you all did a great job of answering my other fashion question so this one is for all of you who go to a school with uniform. I have to wear navy and khaki all the time. We’re allowed to wear any kind of jewelry and shoes as long as our earrings aren’t bigger than a quarter, but i’ve never really tried make it work for me. Any ideas on what I could wear with khaki and navy blue to make my uniform less boring?