I think a director must have:
1. Strategic thinking: to find out the business position and direction to the goals;
2. Management skills: to bring the business to the goal a director need all necessary hard/soft skills in human resource management, operation management/project management, some accounting ability and technology know-hows etc.
3. Business evnvironment knowledge: most of important things, he must understand the inside and outside business environment and can identify what are the most important impact factors.
At last, it is easy to say, but difficult to do. But just some ideas.