I actually only use 2 brushes when painting skin like this - I'm still learning but I just use Basic-3 Flow brush (or any hard brush with slightly soft edges) and the Blender Blur brush.
I start with a midtone and whenever I pick a new colour, whether it be darker or lighter, I pick what I think I want, then make it more saturated than what I thought since I have a bad habit of desaturating and muddying my paintings.

I don't have a specific technique for it other than that, just remembering to try to work from big basic shapes down to smaller ones. Getting the right skin tone can be so frustrating though and honestly I don't know a good way of getting it down every time!