After taking a shot with a firearm, wait at least 15 - 20 minutes before starting to look for the animal. Bullets kill by hydrostatic shock, so the animal will drop relatively quickly if the shot was well-placed.
Arrows, on the other hand, kill by cutting blood vessels, leading to exsanguination (blood loss). Animals can take quite a deal longer to expire when shot with an arrow. Patience is a must. If a hunter tries to track the animal while it is still alive, the animal will run away and try to hide in a safe place - making it more difficult to find.
Hunters should always aim for the heart and lung area, however it is possible for even the best hunters to miss their target and hit the animal somewhere else. If you suspect the animal was hit in the gut, it is advisable to wait at least a few hours before tracking the animal. All deer will expire if they are shot in the gut - tearing the intestines will quickly lead to sepsis (blood infection), but this can sometimes take hours.
After waiting an appropriate amount of time, the hunter can start to track the animal. Look for drops of blood on the ground or on surrounding plants to give you an idea of where the animal went. This might also give you a clue on where the animal was shot. For example, if the blood is plentiful the animal might have been shot in the heart or a major artery and should be close by. Blood that is frothy or bubbly indicates the animal may have been hit in the lungs, whereas very dark blood may indicate a hit in the liver.
While tracking, take your time and observe everything. Mark the blood trail with flagging tape to show the general direction of the animal. If you lose the blood trail, return to the last clear indication and try again, moving in increasing circles until you find the next drop of blood. You might have to get on your hands and knees, to look for the next drop. It is every hunter's responsibility to find any game they shot. This can sometimes take hours, but you must not give up. If you suspect the animal ran onto private property, contact the landowner and get permission to go find the animal.
Important! Responsible hunters avoid hunting in the rain - rain will wash away a blood trail, making it extremely difficult to find an animal.