Hello! I think the biggest issue here is with the face and hair. The back of the head adds a lot of volume that your missing here, and it seems like you are doing the + sign for where to place the eyes, but your curving it around the sphere your making, which adds this curve to the eyes that only exists when theres lens distortion. Unless thats what your doing, I would avoid curving those lines, and keeping them straight. I think once you get that down, I think youll be alright since everything else looked fine, but was distorted due to the way your constructing heads. Just dont forget to draw the back of the skull!! Its something people tend to do when drawing anime because anime is usually seen from the front, and dont consider the back of the head at different angles, which is a lot bigger than you think.
woah tysm!! so that what seem so off now that u pointed it out. i was struggling a lot with how to placethe eyes correctly so i did decide to use a guideline but ig i overdo it, as for the head i was js drawing on autopilot i couldve sworn it was not this small lol. ty that was really helpful <33