Guardian Levels
You could also have a progression system:
Seeker
Learns the Seven Principles
Guardian
Takes the Oath
Completes first acts of service
Sentinel
Completes community projects
Mentors new Guardians
Luminary
Leads a local Guardian Circle
Teaches the Principles
Elder Guardian
Recognized for years of service and wisdom
The Most Important Rule
Instead of asking:
"What do Guardians believe?"
Ask:
"What good have Guardians done this month?"