1. Go Make Your Movie
This is the most valuable piece of advice I can give you. It is bleeding obvious, but it is the point where most people fall down. While making a film is an incredibly draining and time consuming process, it easier now than ever to go out an make a short film that looks great. DSLR cameras, consumer editing packages and cheap VFX have made filmmaking incredibly accessible to anyone who is willing to put the effort in. For merely 500 pounds, I made a 15 minutes, VFX heavy, socio-political action sci-fi that alluded to the alien intervention with human affairs. 500 pounds sounds like a lot but most short films aren't trying to be that ambitious and take place in one location. Many short films are made for absolutely free. You would be surprised how easy it is to find actors, sort out a location and find equipment. I find many people convince themselves that the idea of filmmaking is unattainable to them because there is some sort of secret test they have to pass. It is not true. The only thing stopping you going out there and making your movie is you. So go ahead, make an enquiry today. Call a location or post an advert on a casting website. Consider it the first step into being a film director.