I look for anything out of place if I don't have any blood, and I also look high for blood. I've had situations with no blood on the ground but I'll find it on the tops of grass or on the side of trees. I look for tracks if the ground permits but if not I look for broken twigs, pushed over grass, or even a kicked over rock. I've also found that in alot, but not all cases bears and elk can be the worst for not leaving alot of blood.