Team work is the buzz word in MBA.
In allmost all industry MBA Grads go into, they have to work in teams to execute a project. That said, instances of team work doesnot have to always come from your work place (though it would be considered good if it did)
Okay let me take a shot at your situation.
So you are a teacher now. I guess coducting your day to day activity doesnot require much interaction with others. But surely the school must be holding events where 2-3 teachers would form a group and organize everything. if you have participated in such an event that could be a good point to start.
Another situation that comes to my mind is the regular faculty meetings. Faculty in itself is a team and obviously the faculty must be meeting to discuss various issues facing the school or new initiatives to be taken. Take out examples where you had to convince your fellow teachers about a initiative or gave a resolution to one of the issues.