With the deer on its back, make a shallow cut through the skin just below the breastbone. Make sure that you start your cut well away from the brisket, allowing plenty of uncut skin for your shoulder mount. Insert two fingers of the free hand, cradling the blade, to hold the skin up and away from the entrails.
Cut straight down the belly and around the genitals, separating but not severing them from the abdominal wall. Slit the belly skin all the way to the pelvic bone.
Cut deeply around the rectum, being careful not to cut off or puncture the intestine. Pull to make sure the rectum is separated from tissue connecting it to the pelvic canal. Pull the rectum out and tie string tightly around it to prevent droppings from touching the meat. Lift the animal's back quarter a bit, reach into the front of the pelvic canal, and pull the intestine and connected rectum into the stomach area.
If you want to make a full shoulder mount, do not cut open the chest cavity. Cut the diaphragm away from the ribs all the way to the backbone area. Reach into the forward chest cavity, find the esophagus and wind pipe, cut them off as far up as possible and pull them down through the chest.
Roll the deer onto its side, grab the esophagus with one hand and the rectum/intestine with the other. Pull hard. The deer's internal organs will come out in one big package with a minimum of mess.
Caping, the process of skinning out a trophy animal, is best left to the taxidermist. Their experience skinning, especially the delicate nose, mouth, eyes, and ears is invaluable toward producing a quality mount. Damage to a hide is costly to repair. Some types of damage simply cannot be "fixed" by the taxidermist.
Many trophies are ruined in the first few hours after death. As soon as the animal dies, bacteria begins to attack the carcass. Warm, humid weather accelerates bacteria growth. In remote areas, or areas not near your taxidermist, a competent person may be required to cape out the hide in order to preserve it.
Every taxidermist has a preferred method of caping a hide. Contact your taxidermist prior to your hunt in order to get instructions on their caping requirements. However, the following techniques are generally acceptable.