That’s it. But being proactive and doing the right thing is often painful and difficult, so people avoid it.
We typically think of leaders as people being at the top of an organizational hierarchy, but everyone in an organization can be a leader according to this definition. Leadership doesn't arise from assuming a role, it arises from using one's role to further the objectives of the organization.
You don’t need books and instructions on how to be a leader. You just need to step up to the plate and have the courage to be one.