As simple observation will not capture the complex leadership developed by effective leaders, interview the leader. Ask them to describe their leadership style, behaviours, traits and their use of power and influence tactics and see if you can confirm with your observation of what you perceived earlier.
Using the ideas and knowledge you have gained from the course to guide you but keeping it open ended, ask them what they think are the characteristics of a good leader. Encourage them to be specific - a good way to do this is to ask, after their initial responses, that they give examples or stories that illustrate when they felt they displayed good leadership. Then try and get them to focus on the skills, traits, styles, behaviours that enabled them to be an effective leader. Also what they think it takes to lead successfully based on their experience and what not to do. Again, you must demonstrate your ability to link the theories, models, and concepts to support your interview.