This is my three year old's room.  I did not want a themed bedroom, so what did I do?  Worked with opposite colors on the color wheel!!  Always works!  I love that it is classic, and that he will not outgrow it for a while!  I went with less is more on blackout panels and sewed ribbon on top to give a simple and clean appearance.  I chose also to do a simple wall mural to display pictures.