The challenge is people's natural reaction is to hesitate or resist when faced with change. Through lots of mistakes and miscues, I have discovered the best way to get buy in. Here it is.
People own what they help create. When people help build something, it takes engagement to a whole new level.
Here's some real time examples.
You're thinking about introducing a new curriculum. Instead of just purchasing one, you get samples of 3-4 curriculums, let the teachers review it and help make the decision. You'll get buy-in for the new curriculum because you involved them in the decision.
You're thinking of changing the name of your children's ministry. Instead of just coming up with one yourself, you ask team members to come up with 10 possible names. You then take those 10 and have everyone vote on the new name. You go with the name that gets the most votes. People are excited about the new name because they had a part in creating it.
You are leading in a multi-site church. You're trying to think of some ideas that will help guest families have a better experience during their first visit at the campuses. Instead of trying to come up with the ideas by yourself, you ask the campuses to send you their best practices and ideas for welcoming guest families. From those, you choose 2-3 that can be implemented across all campuses. People receive the new ideas and are excited about implementing them because the ideas came from the campuses.
Bottom line - Good leaders get compliance by creating and distributing...great leaders get buy in by empowering and involving.