use an orthoganol design. i did this in my room -
on one wall, take your two fav. colors, and some painter's tape... make patterns with the tape on the wall - i made squares, but the lines aren't straight - makes for a VERY cool effect - then paint every other square with your two fav. color - min is blue and yellow - then peel the tape off... for a better effect... - go to home depot and buy some disney stencils - i bought the castle, mickey's head and mickey's glove stencils, and go back with alternating colors and put a stencil in every other square up and down- real cool!