For me personally every time I go to the dunes I always make my own little course and then just run laps. Where ever I feel not as fast I just keep runnin that spot until I get it down. It?s made it so whenever I go trail riding I feel so much more comfortable in wash areas, or sandy spots on trails. Or in your case, a sand track. Just practice, practice, and practice some more. It always helps to have someone faster than you to ride with also.