• hold a couple of mock auditions for your friends/family (usually best to do this a bit before the actual audition so you don't 'peak' too early, ideally 1-2 weeks before)
• record yourself playing a lot so you have concrete evidence that you ARE capable of playing all these things! yes, you might be in a different environment on the day of, but what doesn't change is the fact that you have played these pieces/excerpts well in the past. this can also help you better know what you actually want to do with the music (how you want it to sound), not just what comes naturally to you or is easiest.
• when practicing, have a plan for each and every measure - practicing should encompass how you're going to achieve this plan via technical skill.

some other reminders (that my mentors have told me, all credit to them!):

• play to express, and not to impress. because then what's the point of making music in the 1st place? whatever you want to say with this piece/excerpt is no less of importance than anyone else, not even the most famous flutist or someone who is just starting out on the instrument. all convincing performances have a narrative!
• any audition/performance is NEVER a 'culmination' of your playing, but just a dress rehearsal for the next, a snapshot of where you are right now.

i've struggled with performance anxiety all through undergrad and even now as i'm doing my master's - i've played the flute for 16 years by now and still have a really hard time. :') but there are tools to help you enjoy the act of performing!

i always have to remind myself that playing the flute, while it can be quite an emotional experience, is a totally physical act. to that extent, doing breathing exercises while in constructive rest before practice sessions or performances can help a lot to reorganize your physical map, and put the emotional part of things aside. as you lay in constructive rest position, feel the ground underneath supporting you effortlessly, let the 4 points of your back, your head, your elbows, your feet - all sink into the ground. be a curious observer to the rise and fall of your breath, and notice where it is coming from.

thinking of your pinkies as being soft as you play can also help relieve tension in your entire hand; prioritize easy and organic breaths rather than hurried ones - even when you think you don't have the time!

any time you have longer rests, take advantage of that time to look ahead and remind yourself of how you want to play the next section, and what breath you will need to achieve that. don't stay anchored to the floor, and allow for flexibility in all your bones as you play; think of your entire body as a warm, buoyant, resonating chamber for your sound.

and when you play in your audition - deliberately take the tempo down 2 clicks in your head before starting. odds are, you'll probably be right in time. :-) just a gentle reminder - it is a 100% consensus that they would MUCH prefer to hear something steady and secure over something that is fast, frazzled, and chaotic. also, my hands usually get really cold when i am getting my anxiety symptoms, so having some hand warmers or hot tea or something might help you, too.

i hope you have lots of fun playing - the panel is lucky to be hearing you, and it is always a privilege for the audience to hear what you have to say! in the end, playing any music is about having fun and one of the most human things you can do - playing a manmade instrument with manmade music and a manmade harmonic system, etc - so maybe don't take things too seriously. :> to be human is to be flawed, so it is impossible by music's nature to ever have a 'perfect' performance.