Looks like youre working cylinders which is great practice. The ellipse on some of them looks a bit squished and flattened. One way of observing ellipses and seeing exactly what they do is to take a clear glass that you dont care about and draw a line around it with marker. You can use another glasses edge to keep the line consistent around the one you draw. Or use a piece of string around the glass. Once you’ve observed it from various angles and points of view then start making them up out your head. Its a good exercise that help me a bit. I could do with doing again. At their basic shape an ellipse is just an oval. They also sell templates for ellipses and ive had one before but never used it cause i want to understand it for myself. Good luck hole that helps