Brian Halligan, co-founder and CEO of HubSpot, illustrates leaders' duties with the image of a bus trip: set direction, pick up people and make sure there is enough gas in the tank.

First, set direction, or define the strategy. It has to be clear and shared enough to inspire people to join the trip and help you en route. They need to be excited about it. Second, choose the right people to pick up, and know when to let some hop off along the way. Also pay a lot of attention to retain them as the trip goes. Third, make sure there is cash in the bank to get to the destination. And I'd had a fourth one: get the ball rolling. Make sure you help people achieving their mission.

Decision making evolves as a startup grows, but those duties seem to be the bottom-line of every successful leaders.

Source: https://hbr.org/2016/03/how-decision-making-evolves-as-a-startup-grows