Form and space/3D drawing and perspective projects

Form and space/3D drawing and perspective projects - student project

Form and space/3D drawing and perspective projects - image 1 - student projectHere are about 30 of the 50 for the practice.  I can really tell that some look more 2D and flat than others. My circle drawing has gotten much better, but I need to do about triple the practice on the ellipses. I find it very difficult to get them to look symmetrical.  Also, I've noticed that most of the time when my ellipses are more closed my spheres appear more 2D than 3D. Is there any way to remedy that?

I've added some of the later projects in the class that I have been able to complete.  Form and space/3D drawing and perspective projects - image 2 - student project