How to decorate my room?

My room is pretty small.It's 10x9.5,not including the closet.The walls are plain white and On one of my walls I've put up tons of drawings and pictures and stuff.My bed is purple and the headboard is white.I have brown wood floors.I have a purple rug,a camping chair,y'know with the cup holder and such,it's red.A closet with sliding doors,which are mirrors.That takes up pretty much that entire wall.What are ways to decorate my room to make it look better?I'm 12 btw.