Think long term. Here's two examples:

The relationships you make matter way, way more in the long run than the incremental progress you can make by stepping on people's heads. I've seen it enough times: you can get ahead early on by being cut-throat, and it looks like that behavior pays off. But the rest of us notice, and the people who make it in the end are those who cultivate relationships and who can draw upon that power with good will. People who cut throats to get ahead will find themselves all alone when somebody comes for their throat.

That's also why good managers mentor their subordinates in order to help them move on to better roles. Weak managers hoard good employees because they foolishly covet a strong team in the short term-- they fear attrition because they think it weakens the team, and in the short term it does. But in the long term if you mentor your people you end up with a vast network of contacts all around the company (and the industry beyond) who all feel, in some way, like they owe it all to you. That's real power.