Leadership to me is defined by three most important attributes:

Authenticity:
A leader has to be authentic in their approach towards people, matters and situations. It is imperative to command respect that you have original ideas and thoughts but most importantly you also have a style of your own. Many folks may or may not like it but I believe it is imperative to have a style that you can call your own.

Expertise:
Leadership is as much about inspiration as it is about expertise. A true leader stands for something, they should lead from the point of expertise and not necessarily general best practices. Expertise is the only way in which you can lead smarter folks (in many cases smarter than you), you can probably understand their POV and most likely add value to their thoughts and ideas. Expertise could also be a connecting the dots expertise, where in you can bring together a bunch of different expert skills together provide it a specific direction and turn the sum total into a beautiful piece of product/service/art.

Risk taking ability:
True test of leadership is when you have to stand up for your people, your values and your preachings. A leader would put his neck on the line in making the decisions that needs to be made, but would not vouch for the credit undue. In my experience, leadership can be earned just by exemplifying this one characteristic in situations where team looks up to decision making, decisive outcomes and predicting success and glory in the face of uncertainties.