The Head itself should be 4 big eyes wide:
Half an eye on the left, eye, eye, eye, half on 
the right.

The Ears should be located on horizontal 
lines drawn out from the eyebrows and the 
nose.

OK..Here we are at the beginning. The 
human head is pretty much an "egg" shape. 
the set up for this is to draw a circle 
representing the top of the head and an 
inverted cone for the chin. 

Anime chins are much sharper than 
standard chins. Don't go making an 
arrowhead out of the chin but think more 
along the lines of the bottom half of a heart. 
(the cartoon kind of heart..not the 
biologically correct heart)

The placement of the nose should be located 
on a horzontal line between the eyeline and 
the chin line

On a normal human face, the width of the 
mouth would be determined by the center 
point of the pupils of the eye. Anime 
mouths are somewhat smaller so I use the 
inside corners of the eye as a guide. 
Experiment with whatevers best for you.