Leadership is a complex subject and there are many ways a leader can lead. For the sake of simplicity, let's focus on three key stereotypes: leadership by example, leadership by coordination, and leadership by command.
If you are dedicated, good at what you do, and doing it with great style - you are a prime candidate for leadership by example. In such a case, people do not directly follow the leader, but rather the example he or she sets. Leadership by example is efficient for long term and more abstract goals.
A person who has a great overview and understanding of an enterprise can serve as a mediator between different parts of the system. Leadership by coordination works by validating feedback and ensuring clear communication - it's a way to keep everyone going in the same direction.
Leadership by command is the most direct approach. It works by becoming a recognized figure of authority. (There are many ways to establish authority: personal or professional trust, promise of rewards, fear of punishment etc. or just otherwise clever personal marketing.) Leadership by command is most effective in the short term and for clearly visible goals.
There are a myriad ways to influence people and a leader has to be familiar with many of them.
The best possible situation for teamwork is when each member of the team has complete confidence in the intentions and abilities of the other team members, as well as a clear vision of the goal and the steps that lead to it.
Perfect teamwork is invisible. In such an optimal situation everything goes on smoothly and efficiently, and potential problems are taken care of before they even arise. Of course, in real life people are rarely competent, understanding, trusting, or tolerant enough for such a level of teamwork.
Communication keeps the operation of the team well-oiled and without friction. With a smaller group of people teamwork consists of recognizing the problems as they arise, successfully communicating with the other members of the team, and making the necessary adjustments.
As the teams get bigger and the goals more complex, communication becomes harder to accomplish. To be able to function at this level, the team has to be well-structured. It becomes necessary not only to communicate, but to do so through properly defined channels, for clear reasons, and with appropriate level of priority.
Good teamwork maximizes the effect of communication with minimal overhead. (If it's the other way around, it's called 'bureaucracy'.)