Hello, Mikka:

Congratulations! Finishing these 250 boxes is tough, and it's a great step towards your learning just walking through it. Comparing the earlier boxes and the latest ones, I have noted an improvement in your lines (better accuracy and smoothness) and your overall boxes structure. However, I also note a problem that I had in the past too, and I will try to help you avoid it:

Back lines and structure planning. This is a common problem I have seen on students, don't worry too much about it because it seems easy to fix. It appears because of how the exercise is told, so you can learn from it but it's also a hidden trap for some of us. It's the way of marking how to construct the back of the box that causes the problem and the fix is as simple as avoiding the central back vertex until it's the one left. After that, you can mark the point, see if it has the right convergences and if it does not, you can place another mark correcting any mistakes. Finally, you can join the central dot and enjoy your almost perfect converging box. Scylla has this approach explained in detail in this video. I'm sure that video will help.

Talking about structure, I want to touch this topic on depth because you also missed some convergence lines on the front ones. Back lines are tricky because of the central back vertex, but front lines are just limited to a good planning phase and that's what I want to tackle here. Everything you draw will have 3 phases: planning, marking and executing. Executing is just the mechanical movement of your arm, and I think you are doing great on that one. You don't have problems repeating marks if necessary so marking is not a problem neither. Planning is when your box falls apart mos of the time. It could be related to the previous problem because of the vertex you are constructing first as you seem to be remarking always one single vertex and that indicates that all the planning problems accumulate on the last front vertex every time. Try to remark points early, because the later you fix them the bigger the problem will be and the easier to spot will be too.

The last thing I want to comment is line weight. If you are afraid of it, start confronting that fear because you will be needing that skill on the following lessons. It is really important to communicate the hierarchy of lines to the viewer and one of the best tools for it is line weight. It is as simple as passing another time (or a couple of times) over your existing lines if they need to stand out from the lines under them. Use this to show which are the front lines while leaving the back lines as you have been doing them.

I'm going to request a revision for you to practice those problems because I feel they could slow you down in the long run on following lessons.

20 boxes more (ideally 5 pages with 4 boxes per page, I propose this so you can do them bigger).

All boxes must apply the back vertex last strategy.

At least 8 boxes must have line weight.

I hope it helps and feel free to reach me on discord if you have any doubt. You can also ask anything on this review and i will try to answer as soon as possible.