Let's talk about my own experience. I have worked for two years in an industry company and my mission last year was to organize the "40th anniversary" of the company with my manager. It was an event that included about 400 people (100 biggest customers, 150 employees and suppliers).
It was a mission that lasted 9 months (our baby!), I had to prove to my manager that she could trust me, and over time she gave me more and more missions where I felt more included in the organization of the event. I thanked her for that, a leader who trusts you and gives you always some feedback and good critiques that can help you to do better the next time.
We also communicate a lot, for example, we planned a meeting every Monday so we could talk about the project, share some issues that we have, and share ideas to propose the best event. So communication over these 9 months helped us to be clear with each other and guarantee the success of the event.
So, for me, the main key components are:
1. Trust: Give a chance to the employees to participate in a project and let them deploy their skills.
2. Communication: As I said, feedback is important. So communication is a must in people management.