For the first time I felt confident enough to attempt a head. After a few hours I sort of wish I hadn’t started on it :-?. I “borrowed” the ear from Greybeards “van gogh like gesture” thread cause I really wasn’t feeling up to that to be honest.
I still need to do a lot of tweaking. But I can’t seem to get rid of the weird crunch where the eyebrows meet de top of the nose. And I believe the jawline needs some work but I would love to hear some other opninions on it.
The topology looks pretty good, but the mesh could do with some tweaking. Could you post some (orthogonal, shaded too if possible) wireframe shots (with subsurf off) from the front and side views? I’ll post some suggestions then. It just helps to judge where things are out of place. 
I like it.
Look like he’s scared. hehe.
war
Definitely needs some tweaking. I would say that the topology around the eye near the nose needs to be more round, as it kind of is straight right now. Also, that “crunch” at the browline could be caused by several things like unwelded vertices or two vertices that have an edge, but shouldn’t. Other than those two reasons I don’t see why it should, unless its an artifact in rendering or something else in your mesh.
Its a great attempt, I hope to see you make this a very good model.
Here is the wire I’m working with. The bit around the ear needs some serious cleaning, kind of an ugly graft at the moment.
Is it meant to be a male or female head? It’s hard to tell. If it’s meant to be a male head, the nose looks a little feminine, and the lips a little thin. The top of the nose (between the eyes) is pinching because you have lots of small faces close to each other. I would suggest spacing them out so the nose gradually widens toward the eyebrows.
Two more things:
You might find this website useful. Also, try to find as many wireframes as you can and look for commonalities in different peoples topologies. I hope some of this helps. You’ve done a good job.