I use a technique for fur that I learned many years ago from Carl Brenders (top wildlife artist from Belgium). The purpose of the technique is to create "depth" to the fur so that you feel as if you could put your fingers into it. It is VERY time consuming and at times I wonder if it's a waste of time. However, I remind myself that it is like building a house. You have to use studs and joists to frame it out. In the end they do not show, but without them the house would fall down.
The first step is to literally "draw" out the hair coat in a sepia colored paint. Paying particular attention to the way the fur lies and the length of it (in other words short on the face and legs, long on the body).