I can tell you are putting some serious work into this model, so congratulations!
#1; Please tell me that you have a lower resolution version of this model. You have too many edges for an efficient model. Focus on the profile of the skull.
#2; The eyes are too far apart.
#3; I don’t see any ears.
#4; The topology isn’t perfect, but it’s a lot better than the modeling. Take a step back from the edge flow, because it is good enough for now. The edge flow will make more sense once you have spent time on the model.
#5; The biggest improvements will come from careful focus on the profile and volume of the skull. If you need to, use a lateral and anterior image of the human skull as reference planes and match it.
#6. Modeling with this many subdivisions is going to waist a lot of time.
#7. I should have put this first; grab some reference images and draw your topology on them first in order to get a good road map for subsequent child loops.
Keep up the good work, and do NOT be afraid to start from the beginning while applying the principles that you have learned.
Also, modeling with the subjects eyes closed can enable a more objective approach. When you have a human with it’s eyes open, staring at you, it can be easy to feel like you are doing well to create a human face, when in reality there are several key landmarks which have been neglected. Humans see eyes, they think human. What about the nasolabial fold? Or the caruncula? Cheek bones, masseter, etc…