I have been researching Norman Rockwell for this week's biogem. I keep finding similar phrasing in descriptions of his work. I found that he used the same elements of design that the rest of us have. I could identify many of the principles of design which he applied gently or determinedly. My friend Daniel said once that he used an economy of brushstrokes that even Sargent would admire. Others have pointed out the beauty of his surfaces.
There is an excellent explanation of about a dozen of his works in this website,
Norman Rockwell Museum Eyeopeners. You might enjoy seeing how he used design elements; how he used rhythm with repeated shape, color, line; how he balanced the painting with big and little shapes; how he used contrast, defined shapes and posed characters carefully to add interest and drama. Things most of us can learn to do. What we cannot learn is how to make paintings which transcend illustration, paintings which sing. It's part of the reason his paintings are more than magazine covers.
Sometimes I get one which sings, but not often enough.