These look pretty good overall! Your lines are clean and straight which is good and shows you're confident making lines. Box 244 bends a little bit, but for that's the only real glaring error I notice here. You also make good use of foreshortening on several of these boxes, which shows that you have a decent handling of perspective. I'd say overall you demonstrate proficiency with your boxes. Perhaps the only thing I would recommend is to employ line weight more noticeably. For the most part the lines seem to share the same thickness to them and you should try to subtly go over the lines opposite to your initial "Y" once more to add that extra weight.