1) I made a 50,000 poly lathe and sketched my ideas for the head on the base colour map - using symmetry on the lathe.
2) Then I blocked out the masses using flat areas of black and white on the curvy map (This is a fast way to work).
3) I used the smooth brush on the curvy map to even it out a bit, and set the curvy smoothing property quite high.
4) Converted to mesh and added more detail with warp tools.
5) S-Merged it (on its own!) to increase the poly count to 120,000
6) More warp/smooth/pinch and mirroring.