For this one, I was sitting in a barber shop while a customer was getting a haircut.
I told them what I was doing, and they didn't pay much attention to me after that. I used whatever elements of the scene helped to support the story, such as those odd head forms mounted on the barber chairs.
The customer didn't have a mop of hair and beard like that. I kind of made that up, and I exaggerated the barber, too. But I used real details from the scene, like the comb in the barber's back pocket.
I drew the picture with a brush and India ink over a pencil underdrawing, about 11 x 14 inches. I was inspired by the caricature illustration of Al Dorne, Norman Rockwell, and Mort Drucker.
I intended this sketch for The Artist's Guide to Sketching, but it never made it into the book. A book that inspired this thinking is Humorous Illustration by Nick Meglin. Also, check out the more recent books: MAD's Greatest Artists: Mort Drucker: Five Decades of His Finest Works and Albert Dorne: Master Illustrator