I hunt in an area that has a fairly healthy coyote population.
There are other factors as well such as weather, etc.
However, it is extremely important to remember that none of these factors will necessarily make the deer die any faster. You will be only hoping that the deer is down if you go after it before the minimum hours required to let it be for the hit encountered.
For example, if I knew there was rain in the forcast and I knew I was dealing with a stomach hit deer. I would still wait the minimum number of hours required. Even though there will not be any blood trail, the deer should not have went any further then if it would have been dry. But if I push the deer, it will travel. Then I will have no-blood trail and no idea where the deer ends up, I'll only know thatit will be much further then if I let it be in the first place.
sometimes with the bow its hard to see where you hit
I disagree to a certain degree. Yes, sometimes it is tough. But do not try to see te arrow in flight. Concentrate on the target. Do not try to see the arrow at all in flight. If you do this you can even see where a bullet hits an animal.