Are you using references ? you could see where your off or where you have it nailed better like that. You have some of the basic anatomy details fine. its just there placement is off a bit. Forehead is not high enough. Jow line needs to be lower and out more. Eye's are to close to the eyebrows.

Kind of looks like your trying to go a little to low on the poly cage. You could add some edges in a edge loop fashion and it could help much.