Great work on your gestures and cylinders, the ellipses are looking good. Another thing you can try is to add some foreshortening to the cylinders, making the farther ellipse slightly smaller and placing the contour line slightly further away (farther section looks smaller than the closer section. For getting a more exact idea where and how that would look you can use a cube in perspective to guide you first, but after a couple it shouldn’t be too hard for you to make them freehand
Cheers!