step 1 of 4
I've used the Spin Quad-function to spin many of the polys to get smooth surfaces or facial features.
Odd and detailed areas like the nose, mouth and ears are extruded to add more polys to the area.

step 2 of 4

step 3 of 4
These texture layers are applied to Color, Diffuse, Specularity and Bump with small adjustments to make general details to the skin.
The hair is made by using the SasLite plug in several times, with slightly different values for variation.
The sky's generated with the Sky Tracer 2 plug in with a custom sun in the background.

step 4 of 4
For the final render I used Global Illumination and medium AA. It took about an hour to render.

Final result

