Overall you did the exercises pretty good, though I have some critique for the rotated boxes excercise. If you look at the horizontal and vertical rows of boxes, the converging lines on each seem to share a vanishing point, and the faces of the boxes don't seem to narrow. If you take a box in real life and rotate it to the left, it's left horizontal lines will converge, and its left face will become more narrow. It seems to me like you drew the first box too small, concerned with reaching the limits of the page for when you got to the last boxes. This meant you were working with very limited space and couldn't converge or shorten your lines as much as you needed to. Messing up the horizontal and vertical rows has a knock-on effect on the corner boxes, though they turned out pretty good. It also seems to me that the front panels (Closest to the viewer) are a lot better than the back panels, so I'm guessing you did those first. I would recommend doing the back panels first as doing a smaller panel lets you decide the minimum of space you'll work within, whereas doing the large panel first forces you to work within a space smaller than might be comfortable or clear when you get to the smaller panel.

If you redo the excercise, don't be afraid to make the initial box a fair bit larger, remembering that the later boxes will be significantly thinner. Then start each box with the back panel, making sure it gets thinner and it's lines converge more as a rotated plane would. You don't have to redo it as long as you keep these issues in mind (Basically, remember to account for how lines will converge and faces will shrink, practice more extreme angles where one face is extremely thin).

There also could've been a bit more scaling on the organic perspective, maybe do that excercise as a warmup in the future and try start with a fairly large box an or maybe even try starting with a small one and scaling up (Not sure if you're supposed to do that way). The common issues between them and the rotated boxes is that you need to be more confident about taking up space on the page and pay a bit more attention to how the boxes relate to eachother in space.

From now on make sure you don't redo lines, make each mark the final mark even if it misses the dot or the dot itself was placed in a bad position. I've given into this impulse a lot more than you but for the 250 box challenge you need to accept each mistake and commit to whatever you've done. Since you have 250 to do, accept the mistakes you make on each box and use them to improve the next one. It's ok to make hundreds of failed/mediocre boxes if it means you'll have a dozen good ones at the end.

Your boxes are definitely good enough to move on to the 250 box challenge, but you could redo the rotated boxes afteward just to show yourself what you've learnt and where you still have problems.

Last thing, your paper being folded makes it a bit difficult to see the perspective on some of the work, so in the future try avoid that as much as possible or flatten your paper out later. Keep it up!