Lately I have seen a lot of people who are misinformed or uninformed about how one might go about modeling an animation friendly face model. In this page I try to address this problem. The following is a formula that I came up with after some amount of research. You should be able to apply this formula to most humanoid type faces. The steps are simple.
First load your reference images into the viewports.
Now, following the next image EXACTLY, trace the main edgeloops using CRTL+LMB.
Once you are finished drawing in your edgeloops fill in the polygons using the F KEY.
What you should end up with is a model that has edgeloops in the correct position for animation and one that is easy to add more detail to using the fantastic new edgeloop tools (CTRL+R and K KEY).
Finally, I have provided an animated gif showing a quick method for modeling one of the more complex features of the face, the nose.
Here is an example of what kind of results you might get with this technique.
Author TorQ - www.elysiun.com forum member
TUTORIAL AS QUOTED FROM SOURCE