I missed out on drawing yesterday because I jammed my thumb playing volleyball, but today I attempted to draw some cylinders. Cylinders combine both ellipses (circles in perspective) and lines. The approach I took at first was to draw two ellipses first and connect the lines, but that results in shapes that look wrong. Next, I tried drawing the three axes of the cylinder, and then filling in the ellipses around those.
I think the second approach works better, because it is easier to get the shape of the ellipses right. In perspective, a cup or a rod has a flat ellipse on the top (when viewed from above), and a fatter, smaller ellipse on the bottom. Building the internal structure made it easier to get a realistic looking shape. There is definitely room for improvement, but I am still pretty happy with the results.