What are some good room ideas for a teenage girl?

I am assuming that your walls are the light green. If so, to make it more sophisticated add a crisp white and shades of grey and silver. For example, you can use black and white photography and use silver colored frames. You use use shiny silver pillows on your bed and a light to medium grey throw folded at the end of the bed. If you don't want to take out the pink at all right now then the silver and grey will still work with the pink. Then as you get older you can move some of the pink out and you still have a sharp looking room without spending much money! Have fun!