A lot of the elements he uses seem very logical to me. Strong emphasis on layering (as in oil painting, not photoshop layers) and rhythm, contrast in rhythm. Pushing form and space wherever possible. For example in shadows he is avoiding blacks in order to push the shadow's dullness so that the light shines more. He is always planning ahead. Imo his strongest skill is his poetic and aesthetic vision. It's what happens when an artist uses his genius and extraordinary skill to paint something meaningful, and not just robots and dragons.
I imagine that once you master the technical aspects of art and you can rely on your hand to do what it's supposed to, and you understand how light and perspective works, it's much easier to focus on styles and mix them to communicate the depth of life.