Good thinking. You shouldnt go further till you have all the big parts in perfect proportions. I would start by saying that you need to work the roundness of the forehead. Llok for 3/4 reference and look at it. You can even put it in photoshop ontop of your model. It wont fit but it will give you an idea of how off you might be. Areas of the forehead and cheeks are too fat. Always think abouth the skulls even before you begin to think about fat and muscles. Think about those cheek bones and the temporal bone on the head. The same thing goes for the mandible. Think about the proportions of the skull. The jaw is way off. If its a female the neck should be thiner. Get this things done and go to subdv 2 and then go back to 1 to keep refining. Getting proportions early will save you tons of headecks