rob, that photo is heavliy distorted in terms of perspective, so i would get a proper side view to work from
check this site out for ace reference
http://free-textures.got3d.com/natural/free-character-references/index.htmlyou head looks ok, but i think you sohuld post the wires as its just as important how you build it as to what it looks like
couple of popints, the cheekbone seems non existent and the nose has no shape to it, pull it forward more.