This is actually my first time GSing a model, but I do have an upper hand because I do a lot of small-scale detailed jewelry, and my boyfriend is a boss at this sort of thing so I had his advice.
Some of the secret weapons used to GS this:
Needlepoint tweezers (for pulling stands of hair and making a wisp effect) Clay Shapers (Allows you to apply the same pressure as a finger tip but on a much smaller scale. I use them for metal clay and polymer clay too) Slik (Clay balm, apply to your tools before each move and it allows your shaping to be smooth instead of jagged. You could also just use olive oil but that eventually gets sticky. In either case, if you use any balm or oil on your GS stuff at all, give it a good scrub before any painting so the paint sticks to it.)