There are plenty of factors that can fall into this.
#1: Find an area where there is food sources on the ground as well as some good cover.
#2: Find deer trails and follow off to the side of them to see where they go
#3: Find there bedding areas (Can be very effective)
#4: make sure when you are hunting you know which way the wind is blowing. The deer will most often walk into the wind so they can smell easier.