For panos, shoot manual mode. Establish an exposure and shoot all the frames at the same exposure. If the camera compensates for exposure differences across the field of view, stitching will be compromised.
Use a tripod.
Use a relatively long lens, say 50mm equivalent or longer. You can shoot wider, but you can create stitching probems resulting from parallax errors with objects close to the lens.
Conventional wisdom says that sunsets often peak in visual appeal about 20 minutes after actual "clock" sunset.