In a way Leadership is closely related to influencing people, decisions, teams, organizations, etc. Hence in some way or the other it has to be related to human potential development - in other words, in simple words, that which will have to faciliate some sort of growth (needless to say, has to result in some sort of learning as well).
People tend to respond to that style which emphasizes on the opportunities and drives people to learn and grow - one that results in getting people together united towards a cause that is greater than themselves as individuals seperately, in a way those who have the vision and the ability to get people excited about it.
Leaders / Successful Managers don't just wait for Opportunities, if necessary, they create opportunities - I would like to give importance to this factor - if the circumstances are not favorable, leaders need to be able to create the necessary opportunity, drive change (change for the better) and ensure they instill a sense of confidence in the team. That is another thing that any team member or a follower would look forward to, in a leader - a sense of confidence and security that the leader wouldn't let them down in the face of unexpected consequences.
Moreover, there is one another big factor which draws the attention of the people - charisma. This magic word and the magic factor, which many people believe is an asset, is in a way, true! History has proven time and again that charismatic leaders are very successful. This personal quality / virtue / charm / magnetism or however we can call it, attracts large groups of people easily and gives an edge over others for the leader to position himself / herself as the preferred leader (obviously retaining people is dependent on many other factors).
Irrespective of any style of leadership / management, by the end of the day, all that counts is the actual substance. After all is said and done, the most important and the definite thing to look for is whether the leader sticks to his/her words - do they stand by what they have said? Are they committed? Are they ethical?
Last, but not the least, enthusiasm / positive energy is one thing that attracts people! People tend to follow when they are inspired - and enthusiasm is one of the most important factors that results in getting people inspired. Also, passionate leaders are influential and they tend to have passionate followers!