When you're doing the group exercises, they're not looking at the end result, but how you act while you're doing the task. Don't try and dominate the discussion, but try and help your team mates as much as possible. If someone is being quiet, ask them for their opinion, that kind of thing. When you're not doing the tasks, mingle with as many people as possible (don't just head for the best looking girl there). If you can be friendly to everyone the whole day without overdoing it or coming across as a phoney, you should be fine.. .Good luck!