Hello,
I don't have any experince but know that it's important to show your improvement from the first time. eg. Say if you failed because of your english speaking level for the first interview, next time, what I mean next time is that when you are truely ready for the second time, fully showing that you have improvement...CX knows what you did wrong during your first time...Improvement is Important! Just like the Flight Grading, first time they see how you fly with basic skills, and let you know what you did or didn't do wrong, then second time, they EXPECTED you to do a better job!
Good luck, hope one day I'll fly with you!