I'm not a manager, but I've been in some leadership positions in the past, and I can say my efficacy came from my ability to persuade others to do the things I

I'm not a manager, but I've been in some leadership positions in the past, and I can say my efficacy came from my ability to persuade others to do the things I wanted to accomplish, and trust/delegate to others much of the execution. I say this both having executed okay at some things at some times and having completely failed at executing the rest of the time. These constants were there when I was successful and not there when I failed. I found it hard because I approached the problem with an engineering mindset - there is a right way to do things, a solution is fixed or deterministic, and interfaces are efficient. While they may be true in code they are not with respect to people. Often times the right way to do things depends on your perspective, or there is no right way to do things, only less wrong ways. The problem space, like figuring out what customers want/need/alignment between both, is fluid and fast-paced. Interfaces between people are horribly inefficient and communications latency and breakdowns destroy shared understanding and undermine organizational trust/integrity, which in the end calcifies organizations and teams. In this environment, be humble. Recognize that physical intelligence does not matter beyond some basic level, and emotional intelligence will save the day. Always blame systems and processes over people. Be very, very, careful with your words, body language, and actions; understand/appreciate that you start off with less than complete trust because you hold financial/social power over people now, and if you don't want to constantly hold court, you need to actively/consistently build that trust and alignment with your team.