Effective leadership involves your coworkers in a way that they work for their own as well as your goals. For this to happen it must be crystal clear to all team members what these common goals are, and why these are important. These goals derive from a common vision, a mission and a strategy for what the team wants achieve as a whole, and a vision, mission and strategy for each team member separately. In general, your own research group will have to fit in an organization, e.g. the University Department that you belong to, and hence it is important that you know what your superiors have in mind.