Here's a few off the top of my head.

1. Wait a couple hours regardless If It's a double lung before tracking It.
2. Bring a compass or GPS If your not familiar with the area.
3. Good tracking light for at night- Lanterns
4. Toilet Paper for marking blood.
5. Take the blood trail slow.
6. Don't go to far ahead without finding blood. Go back and start all over.
7. Walk on the side of the trail/blood trail, not on it.
8. Keep your ears In tune when tracking.
9. If tracking during the day, make sure you have your bow with. Ask Hunsucker about his friends buck.
10. Look at the height of the blood that's rubbing off the deer on tree's, It could tell you If It's a higher hit.
11. The smell of your arrow will tell you things as well on where It could be hit.
12. When In doubt, back out and take the trail In the morning where you left off. Mark It good before you leave.
13. Listen to what the blood trail Is telling you- beds, lots of blood, not much blood, blood In hoof tracks, etc.

I hope some of this helped.