The proportions (golden ratio)
For modeling a good character it is essential to have good eyes, good sense for the proportions, and understanding the shapes. Nevertheless, it is still worth checking and measure our character’s proportions, and if we did well there will not have much difference. Obviously, each person is different, but there are general ratios (ideal proportions) that (aside from the specific cases) are mostly true for everyone.
The geometry of the face is very important for the facial animation, it needs a right edge flow (this geometry contains only quads).
to be continued…