Teachers work in teams all the time, so here's a brief mini-guide that focuses on personal responsibility and accountability when working in teams. Most of the tips here are applicable to teachers and school staff, though some apply to commercial ventures.
One of the best ways to make teams work is for team members to focus on THEIR own contributions, and much less on what other people in the team are doing. That's our starting point.
Note: You may find ideas and tips to use in your classroom to, since teaching kids to work in teams is part of the teaching process.