When discussing a painting you would discuss the use of

How they stroke there paintbrush and how light and dark the color is or how thick it looks and how realistic it is and mostly what is the main reason or a hidden message about the painting.

The meaning and the focus. How the artist felt and the strokes of the paint brush, colors, mood, theme.

soft,hard and rough for soft would be a pillow or a stuffed animal hard wood floor or a table rough paint

classical and renaissance ideals. he mainly focused in historical paintings, so you could also say that he drew his artistic inspiration from the bible, since he depicted and painted many scenes from it.