Answer:
Wavy half-up style like this pic
http://charmingwomen.googlepages.com/6.jpg/6-medium;init:.jpg
tart by applying a styling product to wet hair and then use a large round brush to blow-dry the hair smooth. “Divide your hair with a center part, then take a large curling iron and wrap the hair from mid-length to the ends around the barrel of the iron, curling all the hair in a downward motion,” says Smart. Pull a small section from each side of the head and bring together in the back and secure with a bobby pin or hair accessory.
After you finish curling the whole head, let the hair cool down and then run your fingers through the curls to give the soft, separated waves.

{ 3 comments… read them below or add one }
If ur dress is strapless u should wear is down and wavy but do a deep wave look in the front, like those old 1940's actresses type of look. Have fun at the prom
Depending on the dress, you should do a nice, loose updo.
Or you could wear your hair down and curly( :
Down, to sit on your shoulders and curly