Hy, maybe you should draw from observations, 1min drawings draw a lot of poses but not only the head try to draww a full body, in the real life the head is alway with the rest of the body. So draw a full body, your not forced to details the head just like a mannequin with no details, and when you start to understand the how the head is hooked to the body and how it interract with you can draw full body in 5 min, and if you think you are stuck just add more time.
if you draw every days full body with head , i think that will help you to understad the form of the head and that will help you to understand easly the forms of the face. Don"t forget to start never draw from imagination, but a lot of observation to understand the face the forms the light ect...
I hope that will help you, i do theses exercices from a month and that reaky help me to draw ealsy faces.
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