Let people have some skin in the game
Half the creative director job title is "direction," but that doesn't mean you have to run an autocracy. And while I think this has always been the case, new media has made it an imperative.

Compared to past campaigns, today's campaigns cover a vast range of media and vehicles. And all of those elements are key to optimal campaign performance. There isn't any way a creative director can know everything across the spectrum. And everyone knows that. But you need more than just other people's advice. You need them to care. You need them to be emotionally committed to making the campaign the best it can possibly be. And people do that when they're inspired, not coerced.

So, keep discussions as open as possible. In advertising, today more than ever, a great idea can come from any corner of the office, at any level. 

Learn about other sides of the business
Creatives need to know how to make great pieces of communication. Creative directors need to know things like how those campaigns fit in with the much bigger picture of the client's long-term business goals, their brand personality, their marketing objectives, and even what they have to spend on all of that.

I recall an article about how John Lennon was always able to speak very specifically about a broad range of instruments and the way they could be used. This always earned the respect of his fellow musicians in the studio, despite the fact that they were obviously more technically proficient at those instruments than him.

The same can be applied to working with anyone throughout the campaign process. The more you understand a given area, the more you can engage the people working in that area. And that leads to cooperation in the near term and more effective solutions in the long term.