warm ups are very individual. For tomorrow, do whatever you do before your workouts.
Some people will jog a mile, do a few strides, and stretch out. Or just sit around. I like to do a more comprehensive warm-up, and I try to minimize any down-time between warm-up and race.
I do:
15min jog
(bathroom)
dynamic drills
(bathroom)
4x100-120m strides in racing spikes (started 15min out from race)
catch my breath, then 2-3min at anaerobic threshold
if it's a long race (5k and up) I do nothing else before the start. If it's 3k or less, I do 4 more accelerations over 80m or so.
I'm floored by how little warm-ups some people do. I've found that the more I add, the better I feel in the race. The 3min at anaerobic threshold especially helps. Got the idea from an interview with Jack Daniels.