Always have a Plan B


There will always be something creeping up when making your film, so it is a good idea to have a plan B to your main film, and a plan B to your plan B, and so and so forth until you got every variable under control to where you can just start filming.

Hope for the best, plan for the worst.
It's true that will always be something that comes up. However, I've also learned that you'll never have everything figured out in advance. Pick a film that you think you can reasonably make and just start. Starting is the real key. Once you get the ball rolling, you can figure out the stuff that comes up.