Hi there, first off, I think your Ghosted Planes and your lines in general look very confident and straight which is really good! As well as your ellipses, they look very neat. With that first Superimposed line exercise, however, I see some fraying at the beginning of your lines so make sure you are taking the time to think through your starting motion before putting pen to paper.

On your Funnels, I see some of them are not cut exactly half and half (ie. some are on a tilt or angle in comparison to the center line), so just keep an eye out for that.

On Rough Perspective, make sure that your correction lines go all the way to the horizon line so that you can see where it falls in relation to the vanishing point!

On your Rotated Boxes, you are missing a box in each of the corners, so make sure that you know how many you have to draw.

And lastly for Organic Boxes, it might be helpful for you to draw the whole outside of each box, rather than having the front boxes cover up the lines of the back boxes. Not necessarily draw through them all, but at least get the outside lines of each box visible.

Also keep an eye out for too much foreshortening (check Lesson 1: Boxes: Additional Notes: Foreshortening) and make sure to try some boxes that have shallow foreshortening as well. Remember that each line (in this exercise) is meant to be parallel to one of the 3 lines elsewhere in the box.

Sorry if this was too detailed but I wanted to make sure I wrote it all right!