my aproach would be to think about edgelooping first. basically I model the whole "thing" at once, means I dont model the head, then the torso, etc... I create a cube and cut/extrude/whatever. as a matter of fact I use extrude a lot. the extrude operation gives you a mesh which is distributed in a clean way in terms of edgelooping. I then flip faces to alter the loops and extrude again to create a denser mesh.

but you cant get completely away with haveing a highResolution mesh in one area and a very lowResolution mesh in the area beside it. try to distribute the mesh evenly. when you create blendshapes afterwards and try to animate it you will understand what I am talking about now.

have a look at maya´s masterclass DVDs from jeff unay he is called I think. he explanes some really cool hyperrealistic modeling techniques. the best tutorial on modeling in my opinion is from Freedom of Teach - Human Modeling. it doesnt matter if you like human modeling but it shows exactly how to get around the troubles you have.

gl!