Hey there! First of all, I think that the sizing of the general shapes you chose do work well with the human proportions! What threw you off here, likely has to do with your knowledge about the forms and proporitons within face in general. What I'd suggest: 1. Try to apply the "Loomis Head" guidelines to your portraits and take note about what seems to be throwing you off the most. Try adjusting accordingly. 2. Learning about simple measurements. For example: There should be around one eye width of space between the eyes / The eyes should be placed around half way of the whole head / Around the height of the tip of the nose, the cheekbone starts to gain volume upwards. etc. Generally, studying the bonal structure of the skull will also tremendously improve your sense for these proportions and volumes. I hope this helps and keep up the good practice!
