May I Hijack a little?
I see you are boxmodelling. It is much simpler than you think.
Say you have you box in front of you. It is subdived a couple of times, so it should be all quads till now. Your rough box should be subdived too much though and you should push the verts around to make it coencide with the volume of a head.
NOW COMES THE TRICK!
Where you want the eyes and the mouth: select those faces and delete them.
For example, you could delete 2x3 faces of each eye socket.
For the mouth you could delete 1x5 faces or something. Just use your judgement.
Now you are left with those square gaping holes in your head. A nice trick to make those holes more round is, is to select the edges that makes up that hole and hit smooth (edit buttons) a couple of times. Voila! Flatten those holes by scaling them in the width and height (the edges should be still selected).
Look if you can give your box head a more humanoid shape… push the eyesockets in or something.
(Don’t think about the nose yet. It’s a pain in the neck and it will be modelled later)
It is time to make the most important edgeloops on the face: Orbicularis Oculi and Orbicularis Oris (circular muscles around the eyes and nose)
Oops… I have to leave… but I will finish this later for you. I promise…