Once you have figured out your purpose and your mission, it's time to move onto your vision. I have already written a series on vision in children's ministry.
Here are the links to that series:
Why Do You Need a Vision for Your Children's Ministry?
How Do You Develop a Vision Statement for Your Children's Ministry? Part 1 - Brainstorming
How Do You Develop a Vision Statement for Your Children's Ministry Part 3 - Get the Word Out
Purpose, Mission, Vision, and Goals in Children’s Ministry Series:
Introduction – Purpose, Mission, Vision, and Goals in Children’s Ministry