The team challenge is a big commitment. You should carefully consider if you can dedicate the time for the duration of the challenge, taking into account work, education, and other commitments.
Have a decent understanding of the core skills - Modelling, Texture, Lighting/Presentation and use of a game engine
Must be able to commit at least 10 hours per week (that's roughly 3-4 evenings or 1 evening + 1-day minimum)
Actively communicate with your team
Be flexible - Ideally, everyone gets to work on what they want but you may need to do some of the less hero work but that doesn't mean you can't make it worthy of sitting on your portfolio
Little more flex - Teams are often made of multiple time zones, you may have to be a bit flexible to make meetings or figure out a system if you can't
Be responsible for yourself - if you've committed to the team challenge you are expected to pull your weight. If you don't you will be removed from the challenge
English - You'll need a basic level of spoken and written to be able to communicate effectively with your team