If you were to sit with ten directors and ask them that question you would receive ten different answers. That is because each director develops a system based on their experiences crafting and producing plays. Since every individual is different and each artist that a director is forced to work with has different ways of working and communicating, then it is obvious that each director would develop a system/perspective/ideology that would respond to those experiences and allow them to be successful. While those experiences would vary in approach and perspective there are several common factors that will be found in all approaches.
A Director is a leader. The director is the glue holding together the production and is the central hub of communication between all of the elements that make up a production. A director does not always need a plan (although it helps) nor do they need to be the most knowledgeable person in the space. However, they must be an effective communicator and have skills in developing trusting relationships with those they work with. A Director needs to be able to have an idea of what they want, but be open to letting the artists you are working with help shape that idea. As a director you are going to work with difficult people, artists are often difficult, but all people want to be treated with respect and dignity and feel like their ideas have value. If you wish to be a director you will need to be good at dealing with different personality types, you will need to be good at listening, and you will have to get good at both negotiating and compromise. A Director is patient yet demanding. I realize that statement seems like a controdiction but it is not.
A Director demands each participant brings their best work, creates a game plan for success, and is constantly working to improve. Yet, as a director you will quickly find that all of the plans you have made are not possible, or that an actor is late, a designer is behind, or those supplies you desperately needed will not come in time for the show. It is at these moments where you must be patient. You must learn to deal with failure in a positive way. Obstacles force us to be creative and live in the moment and creativity is maximized when living in the moment. Remember when you are in stressful situations that you can turn any loss into a win with the right perspective. Furthermore, you do not need to solve every problem by yourself. You have a collection of brilliant minds by your side that also want your project to be successful. Your creative team can help solve these problems.