Jeff
I think that I'd try to make sure to give myself 'time' and 'space' before the big day. So, 2 days before playing, I'd fulfill every conceivable duty and obligation I have: to work, family, friends, that oil change on the car, etc. I don't want to have any bit of guilt marring the special day. Then, 1 day before playing, I'd hang around a golf course, any golf course, and just think about golf...well, actually, think about nothing much at all. Hit a few putts, stretch out my back, read about the course I'll be playing, but casually, letting it all wash over me.
In short, I'd just try to make sure that, on the big day, I'd have the presence and peace of mind to pay attention.
Peter