Power is the ability to get things done through other people. Some people like to operate from the shadows. You do not know their name, who they are, what they work, but they are immensely powerful.
All human relationships are based on power. With that in mind, power can take one of two forms. One is the influence, the ability to encourage someone to do what you suggest. The second is compulsion, or the ability to force someone to do what you command.
Influence is considered to be more effective than compulsion. The best way to increase your power is to increase your influence and reputation. How to do that? How people achieve that power? This documentary takes a look at it.