Yes, write down the bearings from checkpoints and other critical points. Memorise/understand the lay of the land and match what you see on the ground with the map. And yes, do not follow!
Of course I would never; see a mate ahead and follow him,only to realise he was injured and had bailed out of the race. Doh!
Just follow the person in front, they'll probably be going the right way and if they're not it's better to be lost with someone than lost on your own because you've tried to find your own route and got it wrong!