Any teen girl would feel like a Queen in a room like this Marie Antoinette inspired master bedroom featured in the Atlanta Showhouse. I love the sparkle and shine of the chandelier!  
What cool refreshing wall colors!  Walls and trim paint are teal-tinted Catalina Blue #703 and ceiling paint Hush #AF-95: Aura by Benjamin Moore & Co. Images from here.
This is simple elegance.  The Lilac colored walls and accents are soft and comforting.Image from here.
What a great headboard idea!  The pop of color is really fun.  Your imagination is the limit when it comes to deciding what to put inside the picture frames.  A couple of ideas could be photos of best friends or inspiring quotes!  Image from here.