ATTQOTD: Pretty much what everyone else has said here. I'm pretty tired of stuffing carbs in my face by the day before the race, but will still try to eat a few more carbs, but dinner I try to keep more normal. Lots of water although I know now to mix it up with some electrolytes in the water too now since I start getting a headache if I don't. Also no alcohol. Someone mentioned eating salty chips the night before a race and so I tried it this time too. Not bad! Since most races start early in the morning, I try to get as much sleep as possible and get as much ready so I don't need to wake up earlier for that: clothes, bib, garmin, socks, hat, warm up clothes, post-race refreshments...
I will look over the course to see elevation changes, but a video tour is best if I'm expecting lots of hills.
For my last race, I tried a bit of toast with almond butter in the morning. Coffee (always! Gets things moving). Some water but not too much and a few sips before the race since I get a bad case of dry mouth before the race. Lots and lots of bathroom time. And at least twice at the porta potties if I have time. I'll have a few bananas as well right before the race.
At the starting line, I take some real slow deep breaths to help calm my nerves. Otherwise I'm fiddling with my watch and phone making sure I've got my race playlist going!
It's nice to see others also have that twinge of regret right before a race. Like, why did I sign up for this crazy thing?!? I always have a lot of self doubt the days leading up to the race and regret registering and even training thinking I had been wasting all my time. And I always have imposter syndrome lining up. This is why I take the deep breaths.