INFPs are generally reluctant to lead. Not that they can't. Usually, they simply don't want to, and thus don't get chances to practice their skills. Indeed, an INFP would rather be the supportive follower who encourages their leader and gives them the confidence they need on their quest.
When INFPs do find themselves in leadership positions, they tend to have a style that shows itself in creating an accepting, encouraging environment for people to discover themselves and experiment. They empathize with the feelings of their followers and seek to build consensus around shared goals that are arrived at through open communication. INFPs are "we" leaders who do not want to impose so much as support, channel, and facilitate the will of the group.
However, they may find themselves in trouble when it comes to the inevitable confrontation with the group troublemaker, or the need to lay down the law for the best interests of everyone on the team. Leaders are considered fair game for criticism, and INFPs take criticism hard. These are areas for improvement, not limitations. INFPs can pick up these skills with practice and experience--though there may be stress-filled growing pains.