This is a modern day 'Grease' get up. Try tying the scarf either around your neck, in your hair or even use it as a belt. Pin the pin set down the front of your jeans. You can also try tying the tunic in a knot to shorten it.
Topshop - Basic One Shoulder Tunic - $24US
White Ankle Socks - K-mart - $9.95US
Topshop - Flat Top Sunglasses - $30US