Design the fun, First!This, I can't stress enough, is the Major Principle of successful entertainment product. Make sure the product has a remember-forever experience in it that will get the audience to recommend it to their friends, and keep them coming back in the future. Disney's primary design focus is "engage people's hearts to engage their minds." The first thing they do is design the gags and tear-jerkers and scenes you'll never forget. The Beast's magical rose was thought of, storyboarded, and animated before they even had a story. The big musical production numbers with mermaids and crabs cavorting around under the sea were nearly in the can before they had finished writing the script for the rest of the film. Disney tries to make you laugh, they try to make you cry, the rest of the product serves to tie these hook scenes together. Universal's primary design focus is "determine the demographics, then hit 'em with a product they can't refuse, and get 'em through at 6000 people an hour." As at Disney, the first thing Universal does is design the scenes that sell the product. First they design the best car chase ever, or the most elaborate collapsing building, or the most tense rescue operation, something to show again and again in the trailers. They storyboard their fights and chases and effects; a lof the best footage might be in the can before primary production starts. Trumbull's primary design focus (as a sub-contractor, not as a studio) is "what's it worth to you?". Once again, Trumbull starts with his key images - a bone axe changing into a missile, or a psychedelic trip into the mind's eye. These hooks help sell the project. After all of these disparate groups have their unforgetable scenes, they take their storyboards, paintings, and filmclips to the studio brass to sell the project. The brass give their okay, and that's when they start building a story around the fun.
Lost-in-moose had some interesting thoughts on this post.