In 2019 I committed to improving my industrial design sketching ability by sketching every day. I should mention that I have a drawing background already and am particularly interested in learning this style of drawing, where the aim is to clearly describe fabrication and function.
I particularly struggle with ellipses, so am currently focussing on improving in that area. I'm also working on line quality and learning how to use markers.
In addition to online courses, I'm also learning a lot from Koos Eissen and Roselien Steur's books. Some of the exercises here are lifted directly from them. On the back of the exercises, I was able to attempt the camera.