I recently saw this hairstyle done over at Girl Do's and just loves it! Basically you just need to know how to do a Waterfall braid. (Click here to be directed to the Waterfall Braid.)
You will want to work with wet hair because it will hold it's shape better as it dries.
Comb all of the hair straight back and begin your Waterfall Braid right behind the left ear.
Work your way across the head and over toward the right ear.
Once you get close to the ear you will want to curve your braid back under the original plates. This time gather in the strands that you dropped through from the top braid.
Continue this back over to the left ear and then wrap around to come back again. Keep wrapping back and forth as many times as you like.
On your last level you will want to gather into your braid but not drop any strand through. Finish plating that braid all the way to the ends of the hair and then tuck it up underneath the previously plated braid. Secure it with bobby pins for a nice tight hold.
Add any hairpins that you like for decoration and you're all finished. This also make for beautiful waves the next morning when you take the braid out!