Don't bull****. If you don't know something, say so.
Think about awkward questions you are going to be asked.
"Why do/don't you want to join the Airforce?",
"Why didn't you get five A grades?"
"What do you expect to get out of being a member of the UAS?"
"What are your ambitions?"
Make sure you know what you will say if you are asked if you have a hobby/passion/interest. Expect the interviewer to also be a Philatelist, Ornithologist, Campanologist, or whatever. So don't bull****.
Best of luck.