Modeling heads question

Ok so I’ve gotten pretty good at faces, now I’d like to figure out how to extrude or extend my face to the rest of the head whenever I do it by extruding, I never can seem to figure out how to even out the head so it looks normal, I can create a head without a face, and a face without a head but I’m blank on how to combine the two, any suggestions? My problem always seem to be the number of verts in one doesn’t match the other. And I wind up confused in the end trying to make things match up. Is there an easier method of doing a whole head?

try making a neck as a separate object, then after positioning it, use retopo to construct you mesh over it.
(edit) also, it’s fairly difficult to get good edge flow around the jaw line, imo, so don’t get too caught up in it.

What is retopo?

http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Editing/Retopo

Essentially, what you need to do is to reduce the topology from the higher face/ears regions to the rest of the head. I think there are some older videos on BlenderCookie.com that go over how to model a human head. I haven’t watched them because I took a course by Jonathan Williamson where he discussed how to do that in one week, but from what I’ve seen at the glance I gave them, it seems to be very similar at least in principle, if not execution because of updated tools.