Line work for the most part is pretty good. There is some wobble, but with future studies (especially if you go on with the 250 boxes challenge), this should tighten up. Ellipses are tightly looped for a lot of them, but there are a significant amount that have a wildness/wobble to them. Be careful of those (it may be because you notice that they aren't going to hit neighboring ellipses or the frame, so you try to compensate, or that you want to hit them, but as a result, they are wobbling).

For the rough perspective homework, you need to extend your depth lines back to the horizon line in a different color pen. This is to help you see how far off you may have estimated the vanishing point.

Overall, your method is fine (nothing out of the ordinary except the rough perspective) and you seem to have a pretty good grasp of the line work basics.