Don't rush. Take your time with everything you do. That dosen't mean don't get in there and contribute but think about what you are saying and doing before hand.
I was recently successful at an interview and during that interview I was pouring some water for myself and a couple of other candidates in those flimsy stiro cups and it fell over and water went everywhere. I just took a deep breath and mopped it up and refilled the water and sat back down. I didn't look to see if anyone had noticed I just fixed the problem and got on with the day.
It also probably helped that one of the Interviewers had done the exact same thing 10 mins before.
They are looking for people that can handle themselves in a situation whether that be to dive in and take charge or to think about the best course of action. Whatever your style just be confident and thoughtful.
