Bloom mentioned that how you package your materials to present to distributors is important. Put as much material together as you can. A trailer or rough cut with a script is okay. That kind of assumes the distributor doesn't know much about filmmaking. A short with a script attached is a good idea, but it has to show potential.
Shorts are usually best at expressing a good idea or story briefly.
It must be clear that it has feature potential. Yet the distributor has to hedge his bets in case it isn't the next indie film blockbuster. So there immediately is a conflict in the relationship. When the film is picked up by a distributor, there are important financial considerations. The negotiations are usually handled by an agent or an attorney.