If you click on my sig, it links you to my tutorial set, it has an unfinished head modelling tutorial (Unfinished because my comp screwed up half way through) But I am start a new set of tutorials, this time in nice pdf's.
My advice would be use front and side referance images, they always looks so much better that way, you can customise your model, it doesn't have to be the same as the ref, but the ref is good for guidlines and anatomy. Also, if you're going for the low detail look, never ever smooth/subdivide, I find it gives an ugly results, try more manual methods of rounding things off. Also the 'knife tool' is your best friend...Heck, all of the tools explained in my 'All round 3D tutorial 1' are pretty much good friends, although one tool is missing from there and thats face extrusion.
Also, generally there are two types of methods in character modelling (but there are more), I prefer the more 'poly method', but the fastest is box modelling, however I am not a fan of box modelling unless I need it. Of course in time you will experiment with stuff and pick your own method to use.