Last skull study is really nice! Definitely draw more from life. Draw when you are in a bus or train or at school taking a lunch brake, draw random objects around your house. Draw your hands, draw self portraits through mirror it'll help you so much more than drawing from photo reference. Keep up the anatomy studies. The posemaniac stuff look's great but always remember what you draw from life beats everything else by tenfold because you learn so much more from it. Keep up studying vilppu and take in some Bridgman as well.
All the best.