Posted here is a drawing I did some time ago, and I cannot remember which client I originally created it for! (I posted it in two segments, enabling it to be seen larger) The line work was done with black gouache using a brush, on top of a background of various big swashes of color, probably with watercolor...
I think it was for a travel magazine editorial assignment, obviously on the topic of upscale cocktail parties in the city. Throughout my career I have always enjoyed doing scenes with a lot of characters... but from a practical business standpoint, creating a scene with so many different characters takes far more time to execute than an image depicting just a couple main characters. So, if a higher fee at the start of the project assignment cannot be negotiated, it ends up being a labor of love... because the fee usually will not match the number of hours it will take to complete such a dense image.
Whenever I draw characters, I never use any reference what so ever, unless of course I am doing a caricature of a real person, then I will refer to a photo. When creating faces, I simply draw from my imagination... and living in a city of 9 million people helps. Because after years and years of seeing so many different types of interesting faces on a daily basis I think a kind of "facial type" memory skill is developed! -in this image, I especially like the little guy with the pencil moustache (in the bottom panel) directly under the waiter's arm. He looks like a young James Lipton!