You should ghost your ellipses where you wan to place them then once confident with the motion, draw it in speedily. Those ellipses look rushed and as if you drew them very slowly, trying to make them align with the axis. There are some places where there are bends and corners on the circumference of your ellipses. This is an issue of your basic ellipses, you are not drawing them confidently. You should as above ghost them until confident and draw them in in a smooth motion. In many places the ellipses you have does not align with the axis. The axis should be equally divided by the axis.This is not a problem with lack of a ellipse guide, these you can do without one. The detail you added to the wheels look rushed , you should take your time observing the forms that are making up the rims of the wheels and consider their angle. work slowly one line at a time.

" I'm currently working on trying to keep my ellipses confident " -> I will ask for revision, take a page and fill it in with ellipses. Fill the page with ellipses that are touching but not overlaping, so like placing balls of different sizes together in a bowl, touching but not overlapping. The approach to drawing each of these should be to ghost the ellipse from the shoulder with a good amount of speed, then once confident. speedily fill in the ellipse. It should not be drawn in slowly.

did you do the 250 cylinder challenge ?