Hit the jumps (heaps of snow) and do tricks to score points. While in mid-air press:
"A" to do a 180
"S" to do a flip
"D" to do a side kick
The more tricks in one jump, the more points. But, make sure you complete your tricks before you land, or else you will end up in a huge wipe out. Also, the more successive jumps you have without hitting an obstacle, the more points you will earn. Good luck!