As with everything in life, this will be a learning experience for you! Over the course of the first year, you'll find your own way and surely find your own set of things to watch out for. Until then, let me point out some things I've learned:
1) If you are a brand new teacher, I don't think I'd try this quite yet. Definitely do try a little here and there, but don't dive into the whole thing. Why? Because, when students learn on their own and do group work, they come up with some REALLY weird questions -- much stranger than what's typical. One of the biggest things a new teacher learns is how to field questions from students... It's better to start with the typical questions first. If you've been teaching for a couple of years already, I think you're good to go!
2) Try your best to not have tribemates sit near each other during challenges. The last thing you want is for the tribes to form "cheat groups!" Yes, you want them to help each other -- but, NOT on exams.
3) Some tribes may become dysfunctional due to one or more students. Definitely step in and fix the problem by either removing one member or disband the tribe and put the members into other tribes. What I've found is that it's often just one or two students in a tribe (often just the combination) that are causing the problem. When you split them off, the other kids usually turn right around. The majority of kids really do want to be successful!
4) When you break up into your tribe time, how do you make sure the kids do math and not socializing? I learned pretty quickly that a 10% "participation and attitude" grade really does the trick! I make it very clear to them that the "participation" part is to cut down on the socializing and messing around and that the "attitude" part is to cut down on the "this really stinks" moaning and groaning and the eye rolling. I'll expand more on how to work on their attitudes in the next couple of sections.