My team does pretty well in interviews, so I think that I have some good advice for you. I’ll start with the more apparent tips first (please keep in mind that I’m not a judge, I just have more experience with interviews):
Answer the judges questions as truthfully as you can
Don’t make up that you never had to reiterate a design, don’t lie about team roles, just try and be honest. It’s not really a moral thing as much as it is a “you-won’t-have-to-get-the-whole-team-to-make-stuff-up-on-the-spot” thing. For example, if a judge were to ask you how many times you reiterated your design, and you say that you haven’t, or it was only small changes, when you built a WHOLE NEW ROBOT, your team is going to be really confused unless you planned it first. Another reason not to do this is that the judges want to know how you overcome obstacles, make things better, and solve the challenge. Nobody can build a robot first try with zero reiterations whatsoever. The judges will catch onto that, especially if your whole team gives you “the look” after you say something untrue that they weren’t prepared for.
Presentation and Appearance
Obviously, if you’re at a VEX comp and you look a little bit worse than usual, maybe you’re stressed out, whatever, you can’t really do much about that. But judges pay more attention to what you’re doing and saying than what you look like. Keep your hands behind your back while you’re waiting your turn to speak, make gestures when you’re speaking, keep them out of your pockets, don’t fidget or rock back and forth on your feet, act like you’re talking to someone really important, because you are. Judges are pretty much the people that decide whether you qualify or not and that is all of our ultimate goals. Smile and be genuine, look them in the eye, shake hands, introduce yourself and role, be very polite and respond positively to any feedback that they give you.
When you’re speaking, you want to look judges in the eye and smile. But apart from that, you want to make sure that everyone on your team speaks EVENLY and BY THEMSELVES. Don’t cut a teammate off if they say something wrong, wait until they’re done and make up for it. Although, if they’ve already got something major wrong like, “We have an H-drive and built it 2 days ago” instead of “We have an X-drive that we built in the first 2 weeks of practice” that’s probably not going to look good to the judges anyways since your teammates don’t know what’s up.
That’s about all that I can think of off of the top of my head, but I hope that your interviews go well from here on out. Good luck, looking forward to competing with you!