Mammals such as deer, sheep, goats and bear that you want as a full body mount need extra care and attention in the field.
First, field dress the animal in the usual manner, EXCEPT - keep the cut as short as possible and do not remove the genitals or the anal opening.  Make your initial cut to the side of the genitals and next to the anus.  To prevent fluid from getting on the meat - tie them off under the skin. 
     Below are drawings of the three most common ways of skinning an animal for a lifesize mount.
    #1 is a modified version of the rug skinning method
    #2 is the "short cut " method using shorter incisions on the legs.  This method is preferred over splitting the legs completely
    #3 is the dorsal or back incision.  This method is the easiest to sew up and is the least likely to show any stitches

If your trophy is an antlered animal, please let taxidermist remove, antlers or horns
Measurements A & C are taken BEFORE skinning
Measurements B & D are taken over the meat after skinning