Lines:

These are some mistakes that I made when I started out, so don't feel bad.

The first thing you have to keep in mind is to always start exactly on the dot when you start a line, not in the general area, exactly on it.

Next, spend most of your energy focusing on making your lines straight before you go for accuracy; there is no point in a line if it isn't straight.

Ellipses:

Remember, Uncomfortable told you to draw through your ellipse once or maybe twice, you're drawing through them way too much.

Next, I noticed this on your Tables of Ellipses exercise, try to make your ellipses really round; you're look kind of jagged

Boxes:

For your Rough Perspective exercise, try to experiment with different extremes of box shapes and locations; that will make it more fun.

This might've been a mistake of miscalculation, but in your Rotated Boxes exercise you're supposed to make your boxes turn 90 degrees in each direction. Also, your hatches are really fast and lazy (I made this mistake too). Make sure that they are all treated as lines, treat all lines the same as you would treat any other line.

For your Organic Perspective exercise, you still have to be sure that your boxes follow the rules of perspective, a lot of the lines that should have converged diverged. Remember, lines that face away go together, lines that face towards you go apart.

Also, try more box shapes! You won't go through Drawabox with your mental sanity intact if you refuse to experiment and have fun! Try long boxes, flat boxes, thin boxes, basic boxes, boxes with lots of foreshortening (these are really easy and fun), boxes with not much foreshortening, tiny boxes, large boxes, boxes that face weird directions. There are so many types of boxes to experiment from that you'll benefit from one day! Don't hold back (unless Uncomfortable tells you to)!

In Conclusion:

One of the mistakes that I also made was rushing too much while trying to draw. Drawing requires lots of patience and passion. If you're able to zone out on the outside world and only focus on your work, it will be more fun, it will yield better results, and it will help you improve a lot more than rushing through.

Here's my critique for you:

Lines

Take your time when doing the superimposed lines exercise. Your lines are often fraying at both ends of each line. This means that you are not taking the time to position your pen correctly at the start. It's okay if your lines are fraying at only one end, but that will gradually improve as you aim to get your lines accurate.

Your lines are sometimes arcing instead of being straight. If you're drawing from the shoulder, which you should be doing very often, then try and arc slightly in the opposite direction in order to to compensate for this. Revisit the instructions on the ghosted lines exercise to get a better understanding of what I mean.

Ellipses

You have two ellipses that I can see in the Ellipses in Planes exercise that are only drawn through once. If you don't already know, you should be aiming to draw through each ellipse two or three times (preferably two).

In the Tables of Ellipses exercise, make sure you focus on getting your ellipse lines smooth. Prioritize that over accuracy. Accuracy will come over time as you continue to aim for it. Also, try not to get your ellipses overlapping but rather within the bounds. For instance, in the top row, I can see that you are running out of room, you try to make up for that extra room by overlapping your ellipse of the same size with the one next to it. In my opinion, that doesn't give you much of a concrete goal in terms of placement. If you have to, I would suggest even shrinking an ellipse to fit it in there, so that it touches side and bottom the wall, and the ellipse next to it.

Try to have your ellipses aligned to the minor axis in the funnels exercise. But it seems to me as if you were aiming for this all along.

Boxes

For Rough Perspective, Check that the width lines are parallel to the horizon line and that the height lines are perpendicular to it. I notice you are not really focusing on this, not only by the oblique lines you make, but also in your plotted points of where you plan on placing those lines.

In Rotated perspective, make sure your boxes are close together. One of the main lessons to take away from this exercise is that you can use neighboring lines as guidelines, but some of the space between your boxes are inconsistent, so are not using this idea to your advantage. For example, boxes closer in the center tend to be closer together than the ones further away. Aim for a consistent gap throughout the entire exercise.

Another thing is to check that you understand the ideas of rotating a box in space properly. Even though you don't have to get the perspective entirely accurate for now, you should still think about how your vanishing points will shift along their corresponding axis. Revisit the instructions for this lesson and make sure you aren't making adjacent boxes converge to the same vanishing points.

In Organic Perspective, I feel that you could have used more variation in box rotation. Also try to experiment with overlapping boxes, as it gives a better sense of depth. The perspective of the boxes are quite off, but you will focus more on that when you do the 250 box challenge. For now, prioritize on the other things I've mentioned.