First and foremost when on a trail of a deer never never run , you will spook ever deer with out seeing them.
This is what you do follow trail in a crouch , look very carefully ahead at all times and call ever 2 or 3 minutes and once you get a response and are about 3/8 away from deer on your HM , you do not want to run into him ,fine a good spot with the best view you can get in the direction of deer , now just call him in it can take some time but be patient.
And if you can get to a spot that you can go prone and still see all the better.
Number one rule in real hunting and this game also if you are moving odds are deer will see you first and then you are had it.
If you are motionless odds are you will see him first and that is the key to getting your deer.