Understand that, by now, it should all be routine, even for a 1st or 2nd year racer. If you've raced all season, then you've got the routine already. When you do this stuff enough you'll start to switch into auto-pilot.
It's OK to have jitters. Think of it as free energy that you didn't have in training
Also, don't do anything new or different. A lot of people get the urge to "go big" for a big race and throw on a bigger gear that they are used to...and fall flat on their faces. I did this at Masters Nationals once during sprints.
Remember, to eat well the day before the race. That's what will fuel race day more than what you eat on race day itself.