Welcome to the party.

1) Your Superimposed look good. Some arcing but not enough that I think it's a huge problem(we'll work on it).

2) Ghosted Lines and Planes - These do looks nice. A few arcs as if you're tryin to correct your angle(The line below the words "Ghosted lines" is a good example of this). But all and all good.

2b) Your Circles in planes look very nice. Anything that looks off I'm putting down as your pen not working right.

3) Ellipses Chart and Funnels - These look pretty good too, you're getting the idea down. Though it's hard to tell how many times you've gone over them. 2-3 attempts is good.

4) Plotted - Looks good though you only did boxes above the VP lines. I don't think you are required to do one below but I would suggest at least trying it for a panel or two. You still get the main idea.

5) Rough Perspective - Very nice actually. Your traced back lines hit a nice grouping for the most part.

6) Rotated Boxes - You have a good grasp of rotating. Although the ones on the edge look like they rotate too much compared to their siblings.

7) Organic - They seem fine. I liked that you seemd to use a harder line for the boxes further back and softened as you got closer. That's a handy way of telling relation between the boxes and the viewer besides size.