grapefruit, i completely empathise XD i failed first too, so i learnt 'NOT to be yourself'
and then i passed the second time haha. well dont take it that seriously, its not like i acted as a completely ddifferent person, i just saw the things that I might have done wrong or was lacking and by the next interview i tried to focus on these things (e.g. no matter how much i wanted to say something i should have never appeared pushy or impatient, so i shut up and waited for my turn)
one thing is for sure, smile a lot and be very friendly for the OD, first impression counts the most. the AD: teamwork!
by the way, if you start reading this thread from the beginning you will see A LOT of good info, indeed i think we are not saying anything new here, everything has been said before..
good luck on your interviews
(today im a bit happier because finally i got a perfect CBC! *hopes and hopes*)