What's the best advice on leadership you ever received from a leader?

Never ask your Soldiers to do anything you would not be willing to do. That doesn't necessarily mean that you are going to "shovel poop" with them every time, but you should participate in it at least once.

Reward in public and criticize in private. Never lose your professionalism in front of your Soldiers and never ask them to do anything that you would not do.

It did not come to me directly from a leader but in a book. Many years ago, I bought a book called, GENERAL PATTON'S PRINCIPLES FOR LIFE AND LEADERSHIP. It is a compilation of many of his saying as recorded by a young officer who served with him as we prepared for WWII. The first lesson in the book is one that always stuck with me. That lesson is, "we can always learn from each other." Throughout my military career and continuing civilian service, I have lived by this probably more than anything. My rank and experience did not give me all the answers and I always looked and listened to my subordinates for answers. I have found that people will surprise you if you listen to them.