If the blood is sparse go slow. Get on your hands and knees. Look for specks on the ground and on any weeds and grass. Don't get ahead of yourself. If you lose the trail always go to the last spot and start again. Deer don't always go the way you think they should. I've had tracking jobs that were nothing but very small specks and it takes a long time to do it right. Also always track your deer even if you see it fall. The more experience you get the better you will get at it.