In leafing through some old White Dwarfs, I came across a masterclass for painting a Bad Moons Warboss in Issue WD350(US) (also available here, but you need to log in).
Basically it calls for an basecoat of Tausept Ochre:
A wash of Gryphone Sepia in the receses:
Then a midcoat of Iyanden Darksun+Golden Yellow (a 1 to 1 mix):
Highlights are an equal parts Iyanden Darksun+Golden Yellow+Skull White. I actually added more white as my mixture was a little watery after adding a drop of water.
Here is the result on a non-test model:
So there you have it, I am pretty pleased with this method and the results give the models a little more depth and character.
The White Dwarf article also gives a great little snippet on painting battle damage that I used to cover up a small divit from clipping the model from the sprue.
And here is a poor picture of my attempt on the shoulder pauldron: