In a research of American and Chinese companies, it was shown that humble leaders are significantly more effective than narcissistic leaders with their employees more productive and more innovative. Leaders need to have the confidence to drive their team forward and also be grounded to the reality of things.
Adam Grant points out that it was not only by bringing Chris Bosh from Toronto Raptors and LeBron James from Cleveland Cavaliers to Miami Heat that helped them win back to back NBA finals (2012-2013), Shane Battier also played a key role. Although Shane had his limitations, he studied the stats of other NBA players and understood where they struggled on the floor. Every now and then he offered LeBron tips on opposing players and was able to help him become better. Role players like Shane provide a huge boost to any sports team because they are not as much under scrutiny as the superstars and have specific roles and assignments.
As a leader, you need to have the confidence and humility to lead. You can show both of these traits without looking overconfident or feeble. How? By asking questions, getting input from others with experience and knowledge of the subject at hand and not getting caught up in your own biases and assumptions. Easier said than done but its worth it.