Nick is right - the line management tutorial is great!! One of the big secrets to it is - to do it the same way every time!! Don't guess it's the same, do it regularly, and you should have no problems with your unwind!!
And wind down to the handles on the ground, don't let them rise off the gorund and spin/twist. Keeping everything locked in relative to when you landed the kite means 99% of your twists shake out when you unwind the next time.