My experience has been that the face is the part of a large miniature that requires the most work, and should look the best as it is what gives the viewer their initial impression.
I started by painting the face with a watered-down layer of Vermin Fur. (I used primarily GW paints... if I use a different manufacturer, I will note it in the text.) While that was drying, I should have used Scorched Brown to lay down the base for the hair... but I did that after I finished the face. That is generally not a good move, as one can overpaint some of the hard work you do on the face - but I lucked out this time.
Once the first layer was dry, I went to work on the eyes. I took Elf Grey and painted a horizontal bar across the eyes, where I thought the eyes should be. (I used the grey, because white is too dominant a color to use for eyes.) Next, I took Snot Green and drew a smaller horizontal bar in the middle of each eye socket. This is a difficult step, as you have to get the eyes looking the same way, and not make the iris too large. Next, I took some Vermin Fur and started working on the outline of the eyes. I began far out, and worked my way in gradually so the eye would have the proper proportion.
I worked on the face by using darker colors at the edges (mainly Vermin Fur), and then used layers to build the cheek structure and other highlights with Bronzed Flesh and Elf Flesh. Initially it was too dark, so I had to lighten the layers up. I was pleased with the look, and then took a progress picture:
Egad, does this not look good.... Close-ups of miniatures always show up errors and places where you could do more. I went back and redid a couple of areas, and the face looked better.
Next, I worked on the hair. Scorched Brown was the base color, then I highlighted it with Bestial Brown. That was a bit too bright, so I used Chestnut Ink in a light wash to tone it down. Then I was not pleased with the way the depressions looked, so I added some black WonderWash Ink in the crevasses. (WonderWash is a product that I have used for several years. It does a good job of pulling out the highlights by filling in the low areas and not coloring the highlights.) The face still did not have the character I wanted, so I went back and drybrushed grey in at the temples and on the beard.
But now, he’s got a scar on his cheek! Blast, stupid fat fingers. This probem was easily remedied, and a couple of repeated applications of the appropriate color made him look young and virile again.
Once the face was done, I took a break and painted the base.