How to kill time before the race start?
You have got to balance nerves, anticipation and readiness, while preserving mental and physical energy for the race.
1. Chat with friends and other competitors, but keep your bullshit radar on full alert. People will say the stupidest things about their preparation, fitness, training, etc. That may cause you to doubt yourself. Remember the good training you have done and be confident of your race readiness.
2. Do some light stretching about 20-30 minutes before the start.
3. Sip from a water bottle, or Gatorade.
4. If you can stomach the calories then pack a small snack for eating no later than 90 minutes before you start, maybe a banana or peanut butter sandwich, whatever you like. Maybe eat this before you leave transition.
5. Stay off your feet as much as possible, take an old disposable towel or t-shirt to sit on.
6. Switch into race mode about 10-15 minutes before the start. Don't get amped up too early or you will expend vital energy that you will need for the race.