Desert Cliffs is more difficult than Desert Oasis for a number of reasons.
Ponchomon patrols this track, pushing boulders all over the place, and the sands can really slow you down. Oh, and there's also a narrow bridge to cross.
Stay In The Center: Right at the start of the course is a narrow bridge. The best way to avoid falling off, logically, is to stay to the center. However, if something or someone is coming at you from behind, you can try to dodge out of the way. If you are racing someone side-by-side, feel free to try and send them flying if your Digimon is big enough!
Boulder Run: Soon following the bridge, you will come to a series of turns with Ponchomon patrolling the area. Ponchomon will roll a boulder across the road, so be careful to avoid it.