People have asked me how I got the dramatic shadows in the pumpkin notans. The key was to use a very small, almost point source light at a distance and eliminate ambient room light. I used an LED headlamp about 6 feet away from the pumpkins. The LED headlamp is a great light source for chiaroscuro because it has only a single LED and it is pretty bright, even at a distance. By turning off the room lights, I was able to eliminate most ambient light and this intensified the blacks of the shadows.
I found the most successful arrangements where those where the subject was mostly backlit, with a bit of intense light peeking around the edge. Once the light is positioned, it helps to choose a background that contrasts with the lighting on the subject. I often used a split background with white to accentuate the edges in shadow and black to bring out the illuminated edges.
When working with dramatic lighting, the room tends to get pretty dark so you either need to work from photos or use one of those clip-on booklights on your drawing board.