A lot of the work by professional portrait photographers uses more complex two- or three-light setups. And such setups absolutely have their place and give a wide amount of technical and creative control, but you can also accomplish quite a bit with only a single light. This excellent video tutorial will show you five great one-light setups for portrait photography.
Coming to you from Jay P. Morgan with The Slanted Lens, this great video tutorial discusses five effective one-light setups for portrait photography (and it is a 360-degree video, so be sure to use the controls to look around the studio). Certainly, multi-light setups give you a lot of creative control, but on the other hand, if you are working on location, a single light can be a lot more efficient. And beyond that, if you are newer to artificial lighting, working with a single light to start is generally a good idea, as it will make it easier to build an understanding of the fundamental properties of light and how it behaves. Check out the video above for the full rundown from Morgan.
If you would like to learn more about lighting for portraits, be sure to check out "Illuminating The Face: Lighting for Headshots and Portraits With Peter Hurley!"