What I've found works well and calms the nerves is focusing on the important stuff. The "terrain" that needs to be mapped out is NOT the course. A lot people forget that you are racing against OTHER RACERS and that is the terrain that needs to be mapped.

I look around at the start line and try to soak in everyone and their numbers. I watch how they start and do the first couple of laps, who looks strong, who's moving around the pack smoothly, who's squirrelly, etc. I'll record the numbers of the top 5 in every prime and notice who's in the breaks and who's always up front. Then I just avoid the sketchy people and follow the strong ones around. This typically will always place me ahead of the wrecks.