Good luck with the search and welcome to the site. I have tracked a bunch of deer and for the most part a hard hit deer will take a path of least resistance, stay level or head downhill and often stay on a game trail. Marking the blood locations often gives a good picture of the path so if the blood is sparse then a general path gives a better chance of finding again if you are ranging out from last blood. if you get the feeling that the trail is about to end by either seeing spots it fell or a big increase in blood look for a thicket or blow down. They often will dive into cover and die. I have walked right past a dead deer and only found it by climbing into the blow down after seeing the blood trail end. If you come to a creek I have found them dead in those too.