Hire the right people, and then invest in them. Give them lots of feedback, both good and constructive.
Think through what they can be, and list what they need to get there. Then make it happen.
One of the main things people need to get there is experiences that stretch them. They need to be given a project and then supported and coached to success. This is how to develop them rather then lecturing. Measure your worker. Then give them a big task. Never blame then for errors. You are still responsible. However, give the worker your authority and support. And get your team to support them to as necessary. Get the worker to report back to you on his or her plan and progress.
Let them be in charge, but ask questions to guide and remind.
Another key tool is coaching. Coaching is a process of drawing out what a worker may already know or can personally solve. When you guide a worker to solve their own problem, then you are developing them. Ask questions, have faith that they know more than they have shown. When you do, they will surprise you and themselves at how much there is waiting within them to use. You may find that their idea is better than yours. If so, tell the worker.
Developing workers is a joy, but many people feel nervous that workers will replace then or that workers will fail. Neither fear is reasonable. Your good team will be your glory, and any company that cannot see that is not worth your time. Workers cannot fail if you are on their team and can handle it.
So coach and challenge workers with assignments. You can develop them in less time than you might imagine.