I've got an interview for Steward on Mon 8th, so am also interested in any advice. This question has been asked in previous threads and the replies have always been to read up on the RFA history, what they do, where they operate etc. Learn as much as you can about their ships, names, what they do, where they are (Marine Traffic and Google will help.) You might be asked to identify one or two.
Be prepared for the usual why the RFA and why CR questions.
Good luck with your interview Goose.