That's pretty good! The only thing i would criticise is basic shapes before the shading. The head is bigger compare to the body and i think you can solve this with using basic shapes before drawing the details. For instance : There is a lot of source to drawing head shape well. Also you can search "proportion in human body". I suppose this subtitles will improve your art. Keep working, you're doing great my friend.

Its really quite good and achieves the assignment goals. The only Thing I'd point out is using shadow to define certain areas rather than line. If you study ear references - the inner ear for example is more soft gradients of shadow and light on the shapes/volumes rather than defined lines. Certainly wasn't a requirement for the assignment and depends entirely on style choices too. Again this is well done and fulfilled the exercise. Just something to play with and consider in your art journey

This is looking really good! You did a great job achieving the goals of the assignment. My main suggestion for you would be to try and map out the values in the face more. On the left side, you went a bit too light and lost some of the dimension around the eye. I think you could also bring in a darker value in the shirt as well, it will help balance your drawing out!