For our purposes, let’s say a goal is a specific objective that you either achieve or don’t sometime in the future. A system is something you do on a regular basis that increases your odds of happiness in the long run. If you do something every day, it’s a system. If you’re waiting to achieve it someday in the future, it’s a goal.
For me, the work begins with a rough cut of the film. I can't do much with the script. I've tried to write music to a script prior to seeing the film, but I've found it turns out to be a waste of time.