A little tip or trick i use when tracking a deer use the positon of the blood drops to guide your shot placement. Look at the tracks of the deer, how far back is the blood from the front leg etc. Also look up a ways to the brush in the area (if there is any) how high up is the blood sprayed on the brush or grass. Study the tracks of the animal is it favoring a leg etc? When u find blood great but you also have to think about where abouts am i usually finding this blood? Through this process you should be able to figure out where the deer is hit.