Onto Script Breakdowns! BREAK IT DOWN! As in most pre-production tasks, it seems quite tedious at first, but is meant to save you work and hassles for production. The first thing in creating a succesful film (or commercial) is a good SCRIPT. Without a good script, you won't get a good product.
Breaking down the script is the first step towards visualizing it. Sure, it's very tempting to just go ahead and storyboard, but without first analyzing the script, we might forget important elements in our drawings, which means that we'll have to trash them and we've just wasted our time.
Breaking down the script means to scan it for the elements that will need to appear on screen: main characters, secondary characters, clothing, vehcles, etc. By underline these elements ion different colors, we can quickly see what our scenes contain. We will also see how much time we need to spend in the design of these elements (main characters will be more detailed and researched than someone way in the background.
Another task to do with a script is to do a Shot Breakdown, and that is the step before doing our first thumbnail storyboards. By using cinematic conventions of shot terminology, we write down on the script what we visualize our scenes will look like. Basically, we want to see in our heads how particular shots will tell the story best before we begin storyboarding.
By the way, www.imdB.com, great place for scripts!