Several months before production started, I sat down with Sean Conaty (the DP) and shotlisted the entire film. We had no locations yet, no cast. We were still making the decision of whether to shoot the entire film in Kuwait, or whether to shoot the entire film in Los Angeles. But I wanted to have a first draft of the visual design, to inform these choices.
Eventually, we made the decision to shoot principal in Los Angeles, and 2nd unit in Kuwait. To fully understand the division, I looked over our shotlist, and storyboarded the entire script. This was a second draft of the visual design, and it helped in choosing locations, and forming the production schedule.
But the storyboards also proved useful in a surprising way. For the second half of production, there were some off-set problems that made it impossible for Sean and I to properly plan our shots. The storyboards were a life-saver. They helped us keep focus, and we continued to read each other's minds each day.