At times you're placing your vanishing point between the viewer and your boxes (the bottom box and the box directly above it on the 4th page are examples of this). This leads to you extending your lines in the wrong direction and your boxes becoming distorted because your lines are actually diverging from where the vanishing point would actually be. Here's a guide I wrote that will hopefully help you place your vanishing points and line extensions more consistently. If you need some more examples you can find them here and a simplified guide below.

Other than that there's till room to keep experimenting with proportions, orientations and rates of foreshortening but that is something you're able to tackle in your warm ups so I'll be marking your submission complete.

Keep practicing boxes and previous exercises in your warm ups and best of luck in lesson 2.