Richie's the last chance sketchbook

[darktiste]

I suggest to start with a Center line than i like to put in a reversed triangle to indicate the top of the brow area and the bottom of the nose 

The big cercle over the top brow is the forehead 
The 2 oval inside the triangle are the socket of the eye
The oval at the tips of the triangle is the nose
The 2 line that goes diagonally just under the nose represent the skin covering the upper teeth
The 2 line that goes diagonally just under the mouth represent the skin covering the lower teeth

The 2 oval under the nose will help you create the mouth
The oval under the mouth is the chin
And to finish 2 angle on each side to represent the jawline

I like to use this image to alway visualize my plane

I sometime like to throw in a horizontale line that represent the end of the brow to get a better estimate of the distance between the hairline and the rest of the element.

You can get alot of information once those point are put into relation with one an other no need to be scared to do it on an other layer over the picture if needed but you should eventually just skip it and be able to just visualiaze those line or shape.