I had an interview for Princess over Skype. First thing, know your information about the company! Know how many ships they have, when they started, where they go to, and what your role will be/entail. That was the first question I was asked, and I was so ready!
Also, don't be shy! Smile, laugh if you find something funny, but still be professional. I was interviewed for Junior Assistant Cruise director, and he asked me on the spot to pretend I was hosting an event. I just sucked it up, and went for it. I felt so stupid, but he LOVED it!
Also, tell the truth. You might get the job, and if you don't say what you really are, you could be in big trouble.
Have fun! I love interviews. I suppose I am outgoing and love talking to people. Just show you are motivated, you can take the lifestyle and that you will try your best.
I totally got the job. I hope you do the same! Good luck!