It just takes some practice and luck. It gets easier once you learn some of the patterns of the waves. As for luck, just hope that you get good items like the gloves. If you get the super glove, start racing as fast as possible while getting the checkpoints. The glove will block an infinite number of cars until its time limit expires. Though, be careful on hitting the cars that carries the small checkpoints. If you hit one of those, the checkpoint itself will disappear, which can make you lose some precious seconds. After like 15 tries, I managed to beat this mission with Ralph.