There’s a huge difference between what qualities a director must have and what they should have.
The only “must” have is the job. That is, they must somehow be given the position.
But let’s focus on what qualities a good director should have.
A director should have an abundance of:
Excellent communication skills. They have to able to explain their vision for the film to wide variety of departments from wardrobe, to writers, to talent, to the camera and lighting departments.
An eye for framing and camera movement. One thing that makes great directors stand out is their understanding of camera movement and framing. (Spielberg, Tarantino, Spike Lee, Scorsese all are brilliant with camera.
A fluency with what every department does from craft services (the snack table) to editing and post production. From casting to distribution, the great directors know at least something about everyone’s job.
The ability and willingness to delegate. You should know when to let those around you do the job they know how to do, and listen to those who are the experts in their fields.
Have the strength and confidence to make decisions when necessary. Even when the experts disagree, the director has to be capable and willing to overrule them if that is counter to their vision.
Understand the craft of acting. This goes hand in hand with the director’s communication skills. Every actor is unique, not just in looks, but in process and ego. You want a director who can give a note to an actor without giving a line reading if possible, but has enough knowledge and clarity that if a line reading is needed, they can do that.
Along with communication and a way of dealing with your actors, one should have an understanding of psychology. The director has to deal with a side range of egos across the entire cast and crew.
Have incredible patience, but at the same time enough leadership qualities to get everyone motivated when need be. Some are famous for being tough and surly on set (Oliver Stone has that reputation), but most earn the respect of the crew and cast with a gentle, but sure hand.
A great eye for casting. An acting teacher I studied with said that “directing s 85% casting”. It is certainly a crucial aspect. Finding the right actor means less time having to mold the performance, and a better end result.
Self-awareness. Knowing how and when to pick your battles, Understanding your own strengths, weaknesses, is important.
Surround yourself with the best crew you can afford/find. Always try to find people that are more knowledgeable about their department then you, and once you find them, trust them. Guide them, but trust them.
Listening. Listen to what you cast and crew have to say. They may be offering up an idea that would improve your movie. You don’t want, nor should you have long discussions about every decision, but never dismiss an idea without at least some consideration.
While strictly speaking you can grab a camera and ask the neighbors to perform without any of the above. These twelve ‘should’ haves can take you from a someone who calls themselves a director into a GOOD director.