This a really good post about the leadership lessons learned by General Stanley McChrystal. I haven't read his book, but this links to a quick round up.
16 Leadership Lessons from a Four Star General
In the end, “there are few secrets to leadership.”
It is mostly just hard work. More than anything else it requires self-discipline. Colorful, charismatic characters often fascinate people, even soldiers. But over time, effectiveness is what counts. Those who lead most successfully do so while looking out for their followers’ welfare. Self-discipline manifests itself in countless ways. In a leader I see it as doing those things that should be done, even when they are unpleasant, inconvenient, or dangerous; and refraining from those that shouldn’t, even when they are pleasant, easy, or safe.