If you don't have at least a splatter or hair where the impact happened then it's dang near impossible. Every time I've been able to do it I found hair, meat or splatter from the impact then I was able to follow the freshest sign to the animal (mud/straw kicked up, sticks broke, hair on briars, etc). It's a slow, painstaking process but it's worked for a lot of deer. Another thing is once you come to a point where you lose the sign (and I lose the sign often) I spiral out from my last sign until I find the trail again. I always often look back up the trail I've walked to see if it makes sense.