Here is one of Sundblom's Home in America beer ads about 1955.
His broad brush scrubs the light onto the fabric of the clothes and with a warm and cool light source. Painters like Sargent, Zorn, Sorolla all expressed the form with rich strokes in the right place and careful delineation when needed like in the hands pictured below.
Another of the Home in America series.
I have reduced the illustration into gray scale and rotated it 180 degrees to see the spotting of lights and darks for composition. You can use this device with your own work to design the composition by first doing several small sketches (thumbnails) in black and white and then playing with them in Photoshop. Then go to a quarter size full color comp.