Lines

Lines start pretty confident and straight, good job! Here the issues I can catch:

-When starting a line, you should carefully place your pen on the start of each line so only a maximum of 1 end can fray. Plan each stroke you make carefully.

-Another thing is that you aren't drawing starting and ending dots on each line you draw. On the ghosted planes for example, there are some lines where you didn't place it. Be careful with that as it's pretty important to apply the ghosting method.

Ellipses

Ellipses are looking pretty good too, there are a few instances where you have some wobbly lines, but in general they're pretty confident.

On the tables of ellipses you got some that are floating; the ellipses in the tables need to touch the top and bottom lines as well as the ellipses at their sides, be sure you're aiming for this when you're drawing them.

Boxes

In boxes you've been doing a good job as well, here are a few things:

-On rough perspective, you seem to have trouble keeping some height lines perpendicular to the horizon line, and width lines parallel to it. I know it's hard, but be sure you keep it in mind while attempting the exercise.

-On rotated boxes, you're missing some boxes, check the page of the exercise again to see what I'm talking about.

-In general, you're repeating some lines. No matter how off a line is, don't repeat it. Leave it as it is and keep going to the next as redoing it will make the drawing messier.

-I think there are some lines on these exercises where you might not be plotting your lines; just like in the ghosted planes, you need to draw starting dots and ending dots before drawing any line so you can properly ghost it.

-And lastly on organic perspective, try to make the boxes bigger and get smaller as they get away from the viewer. Doing overlaps helps to show which boxes are in front of which boxes, and you can help to clarify this by drawing a superimposed line on the silhouette of boxes that overlap, to add lineweight.