I think one of the most important things you can do when in development of a new film idea is to have as clear a vision of what you want, before you start production.
For me, selecting the music before I shoot is the most important.
Take Bonanroo for example. I decided to make a timeless piece that could live on beyond and one years genera of music. I decided I would compose a track from scratch.
Feel free to take a listen to the track while you read.
I composed it about a month before we went down to shoot the festival. It was one of the best decisions I could have made.
At the time of production the track was far from fully complete. It evolved once we got back from shooting, but I will tell you that having that track before the shoot and on the shoot was invaluable for the entire team and myself.
It kept us focused on the vision when we were straying from our original plan. We would listen to it every morning before shooting to get us in the emotional mindset of the piece. I even carried it with me on my phone to listen throughout the day.
As a director on a crazy shoot at a festival with constant distractions, it kept me focused.
The final product I think turned out wonderful and so in step with the original vision.