I'm going to repeat the advice that I have heard: hire people who are smarter than you are. This doesn't seem applicable to your situation.
Speaking more from experience... the managers that I have appreciated are the ones whose job it has been to make sure that I can do my job effectively, as well as to make sure that I am doing my job. Basically, a good manager knows the most effective way to help productive and unproductive employees alike, understanding that these classifications can vary even on a daily basis.
Management is delegation - not delegation to those under him, but delegation between them. The most famous buzzword in the corporate world refers to the efficiency of teamwork; depending on the structure of the team, a manager doesn't strictly need to be an expert in whatever the team is doing, but he needs to be close enough to the task to be able to recognize when there's something to gain from rebalancing the workload a little bit. Additionally, he must balance being that close against being far enough from the work to appreciate the whole thing.
This goes for everyone, but managers in particular and especially upper-level managers need to be comfortable with the idea that sometimes the best thing they can do is to just stay out of the way. A lot of times, people will feel like if they're not actively working then they're doing something wrong. That line of thinking can quickly turn "managing" into "meddling."
That reminds me: empathy. Being aware of what people are feeling. It's a basic people skill, which you'd think would be a no-brainer for someone whose job revolves around people, but it probably still bears mentioning. An empathetic person can recognize something that could turn into a problem requiring managerial intervention well before it does become a problem. An empathetic person can also figure out the best way to address it.
Analogies to other professions might be in order. If an office is an orchestra, then a manager is the conductor. That is, in fact, pretty much the textbook definition of a conductor, at least during rehearsal.
Relevant skills are perspective, coordination, mediation, decisiveness, and very keen social awareness. He possesses these things so that the specialists and experts he manages don't have to. He can make the team know he's on their side. To his own bosses, he's their advocate; to each other, he helps them do what they're there to do. Most importantly he needs to earn their respect; if he has it, he can do his own job far better, and so in turn can they.