Tuck your shirt in your skirt and wear it high with the buckle around your belly. This shows your curves more and also more leg. Possibly unbutton a couple of your top buttons. But this has to be pulled off right otherwise it may look slutty.
Oh I used to have a kilt when I wore a uniform a couple years back. This is what some of the other girls did to look awesome: hiked up their skirts when no teachers were looking, wore normal length white socks over their opaque black tights and had them up all the way, wore Sperrys and had the ends looped where you fold the lace in half then wrap it around itself and tuck it in for each lace to slip easily on and off and look cool, and unbuttoned their polo shirt a little bit. Also you could try wearing makeup of you don't already. For your hair you could either curl it, straighten it, make it really curly, do a top bun or whatever they call it, put it in a ponytail, or put it in a normal bun, or just leave it however you wear it currently. Hope this helped!!!