Warm Up in Solo: Before challenging a friend in two-player mode, spend some time in the One-Player adventure to learn the physics and common obstacle patterns. snowrider
Stay Centered: At high speeds, try to return to the center lane as quickly as possible after dodging a hazard. This gives you the best chance to react to obstacles appearing on either side.
Watch Your Rival: In split-screen, seeing your friend wipe out can give you the split-second warning you need to avoid the same fate.