There are a lot of drawing styles that I have seen and tried. Some apply line work liberally, applying overlays to refine the form and reduce noise. Others just know where to place their strokes the first time.
The biggest thing I have trouble with is ellipses. Such a basic and essential form, and I cannot draw them cleanly. I practice over and over and get some tight proportions, but when it comes time to draw a wheel, I have the hardest time visualizing and executing the ellipse stroke needed to fit perspective.
Ellipse templates are great but alot of my professors stopped letting them use them after 2nd year. I found that standing up straight and drawing elipses made it easier because I was forced to use my entire arm and rotate from my shoulder
make sure you’re drawing your boxes in perspective which you draw your elipse in. After awhile you’ll just get good enough to do it without (check out harald belker when he does it). Check out spencer’s tutorial on elipses over at idsketching.com.