Hey there, congratulations on making it through the 250 box challenge! It's a bit of a slog, but I hope you learned a lot from it.

You started off a bit shaky with some reinforcing of internal lines and arcing/wobbling to your lines but by about box 90, you seemed to hit your stride in terms of line confidence. It's good to see you hatched throughout the challenge however in places it does seem rather hastily executed and you missed the opportunity to ghost/plan these out and get extra mileage. Similarly, you didn't experiment much with line weight beyond the first page which was also a missed opportunity for free extra mileage.

Your estimation of perspective trends upwards the whole way through, thanks to your consistent application of check lines and consideration of what this was telling you. There's still some persistent issues you're having, particularly with mistakes compounding on the final lines you draw as well as parallel lines converging in pairs. These are particularly evident on the boxes with more extreme foreshortening but definitely make an appearance in the shallower ones.

Generally these kinds of issues stem from how we think about the convergences of our boxes - we might be focusing more on the vanishing points or the lines with which the one we are drawing share a plane - this is a distraction. You should be focusing on how the angles of your parallel lines relate to one another - those already drawn and those yet to be drawn. The angles of our lines follow a predictable pattern as shown in this diagram wherein the green and orange lines are very similar in angle so as to be almost parallel whilst the blue and magenta lines converge at a slightly steeper angle in towards their shared vanishing point. This relationship is useful to keep in mind as you practice your boxes going forward.