Compositing all the different under-drawing elements for the top half of a double-page spread.  All elements drawn on paper (some on same paper, others on separate sheets) then scanned and composited in Photoshop.  That way I’m flexible and scale things as needed to make the shot work the way I envisioned it. After all the compositing is done, I print this out and lightbox the final pencils.  No 3-D models or sketchup with the backgrounds.  All by drawn by hand.