Who made it? From the personal style, art historian can attribute who made these art works.
Who paid for it? Patrons always have a big influence when artists are commissioned. They can change subjects and style in an artwork, under these circumstances, personal style is not important. So it is necessary to know who paid for it?
Basic words for art historian:
Form and composition (not only two dimensions but also 3D)
Material and Technique
Line (like Durer’s The Four Horsemen, parallel strokes depicts dark sky)
Color: Hue, tonality, saturation.