I put on the Hank Williams and the Patsy Cline and the Rosemary Clooney on vinyl - I'm not trying to be some cool indie-rock person I just love the way it sounds - and throw on a T-shirt and jeans. In Texas we practically come out of the womb in jeans.
The big thing is hydrating the day before the race. I will have 20 ounces of water right when I get up in the morning the day before and I'll drink throughout the day.