Whether a full body or a shoulder mount, mammal taxidermy starts with good fleshing and tanning. Improper fleshing results in shrinkage and poor detail work. There are both good and bad tans done in house and good and bad ones done at different factories. Your best guarantee is to ask the taxidermist how their's is done and look at examples in their shop done in this way. A good tan has soft silky sleek hair and has no bad odor. Below are some things to look for in mammal mounts:

Anatomy
Does the animal look alive?

Eyes
Compare to photos of live animals–are they correct?
Are the eyes symmetrical?
Do they face the same direction?
Is the mount "bug-eyed?"
Are the eyes too sunken?

Ears
Are the edges and tips shriveled and pulled over?
Are the ear butts located correctly?
Are they too large; too small?

Nose
Is it shrunken or distorted?
Are the nostrils plugged up?

Mouth
Are the lips shrunken and pulled out of form?
Are there unnatural wrinkles around the mouth?
If open-mouthed, does it look natural or fake?
Are the jaws placed symmetrically in the mouth?

Feet
Do they look strangely attached to the legs?
Are they shriveled up?
Are they puffy, like balloons?
Can you see wires or rods sticking out of them?

Professionalism
Does the mount look clean and groomed?
Is there paint or epoxy on the eyes or the fur around the eyes,lips or nose?
Is the mount firmly attached to the base?

The best in the field have scads of reference materials. Ask whether the taxidermist uses photos of live animals and3-D references. Tanned skins are generally mounted on commercially purchased forms. Good taxidermists make theform fit the skin, not vice versa. Also ask what the taxidermists does if a hide is not mountable.