Number 1: Practice skills. Mounts and dismounts are everything, and races are won and lost in transitions.
Number 2: Short-recovery intervals with high-HR time trials. You won't get much opportunity to recover, so you have to train your body to recover where it can. A typical routine of mine is twelve two minute intervals at 90-95% maxHR, each followed by 45 seconds recovery, with two 10 km time trials @ 85% maxHR mixed in... often, but not always, like this: [6 intervals, time trial, 6 intervals, time trial].
Number 3: Run. There's a lot of running in this sport.