Add on Rule 49.a. Leaders lead, no matter what their current job description is today. Given any position on the old line and staff organizational chart, leaders will emerge. Leaders are change junkies. Let's face it status quo is boring and for most problems, there is no such thing as the only one right answer.
Leaders are aware of their impact on others.
Always send thank you notes. Encourage your employees tell you what they think, about anything. This is part of what makes them change agents. They learn to speak using the cultural language of their audience. This allows them to evoke emotion.