25 min sketch part of 1 hour class
The head looks very small. I would suggest making the back bigger. There isn't any room for a brain in there. The back of the head always looks round and sticks out. You can look at skulls or other peoples work for reference.
The parts are well proportioned, but I think the lines could be a little more defined Like, try outlining again with a signature pen? I'm using this method, let's work together!