if this is one of your first human models youre doing a good job. The face actually has some pretty good mesh flow, it seems clean in most areas (of course there are some extra edges and 5 sided faces but your still getting the shape down first) I think the problem is that people compare this model to the generic perfect proportioned models that so many modellers make. Correct me if Im mistaken, but the model looks like a somewhat older man, someone aged and not the adoness features.

From a modelling standpoint, one of the major areas you need to fix are the bridge of the nose and the lips. The bridge looks too sharp at the sides, like it was blatently extruded. For the lips, there are no lips. You need to bring them out more or add more geometry. but make sure its subtle.

I cant really tell whats going on with the mesh flow of the eyes, but the facial area of the model has some clean topology to it, not alot of beginners can do this.

And then again this only applies if you are not purposly doing this, and if its a matter of style.

Oh yes, make sure you are using reference. I cant stress to you enough about getting reference to model from. Your work will skyrocket when you base it off reference. You also learn a great deal.