Thank you very much for the thorough critique! I appreciate it a lot. I won't redo lines in future homework/exercises; thanks for letting me know. I'm also still getting used to moving my shoulder to draw so I will work on that too.

I did 2 more cells of rough perspective and didn't redo or white out any lines this time: https://imgur.com/0PQZEz9 (There are a few smudges from my ruler though.)