7. Listen
It is ironic that for a job that is based around being heard, one of the keys to its success is to listen. You all know the stereotype of the shouty director who is aggressive, tempremental and difficult to work with. I have only seen one director like that once before and let me tell you, it was a disaster. That is the job of the 1st AD, don't take it away from them. While before I said have confidence in your idea, never let that lead to arrogance because that in turn leads to ignorance. I know we like to think of films with one authority such as Martin Scorsese, Christopher Nolan or Steven Spielberg but the truth is that their films are the artistic expressons of hundreds of people. Concept artists, directors of photography, make up artists, costume designers and set designers all have incredibly influential roles over how a film will end up. These people are experts in their field and will generally know more about their specialty than you or even a hollywood director. Yes, it is your job to have a vision but your success will be dependent on the ideas of others. It is so important to listen to everything everyone has to say and actually consider their points up against your vision. If an idea is better than yours, be happy to admit it and implement it. Your short film will be much better for it.