Well my first quick hint is that you never and i mean never leave a default 2k texture(headshape aswell) in your cf's, that's the main thing, no matter what, you need to change it, cause it will help out on your knowledge and you're just going to get better and better after some time. I'm not saying 2k's textures are bad, but they don't really look good compared to the nba2k9 one's and etc. Just my opinion.
Yeah, anything I do I make sure get the closest headshape possible to who I want then edit in Blender as necessary.
What tools do you use in Photoshop to get the faces so life-like?