I'm no expert - having completed just 1 race and not being in the sprint finish. Still, I think what the first reply says is spot on - just get out and do some sprint training. When the Race comes it'll all be automatic. If it's not - you're not going to win.

When you're on the road with your buddies and you hit a town line sprint or whatever, are you thinking about your gears or weather you should sit or stand? I'm not, and I'm guessing you aren't either. You just think to youself "If I go hard now, he can't beat me." It's all instinct and experience.