Audition anxiety sometimes stems from the feeling that you have little control over what will happen once you start to play. The fear that one little thing will go wrong and ruin everything is powerful and distracting.
But auditions are not something that just happen to you; they're something that you go out into the world and do. I've found that the auditions where I did well were the ones where I felt like I had control over the situation. The ones where I was excited to share what I had prepared. The ones that I treated like a recital, where I imagined the audience enjoying my performance.
No competent jury is rooting for you to fail. No jury hopes you'll crack on the high note or miss your page turn. They want to be dazzled by you and hear something beautiful. They just want to see what you can do and to find someone who fits the position they're trying to fill.
You can't banish audition nerves by pretending they don't exist or by thinking you're a failure because you experience them. We have fire drills to prepare for the event of a fire; why not have jitters drills?
Try running up and down some stairs before you play your repertoire to mimic the effect that a racing, nervous heart will have on your breathing. Try playing through a cough/sneeze/nose itch to see if you can do it during crunch time. Try playing with minimal warmup time to see what will suffer if you don't have a lot of warmup time on audition day.
Think about all the ways that your nerves manifest physically, emotionally, and mentally, and see if you can find ways to replicate those in a safe, controlled environment. Practice experiencing those sensations and getting through your piece anyway. Practice it that way until all these wrenches you can throw in the machinery are no longer obstacles.
Try using this chart in your audition prep, and use the space at the bottom to include your own techniques! (Click to download):
We spend so much time practicing our music; why not practice the situation we'll play it in? When the physical and mental symptoms of audition anxiety become something we understand, they lose their power to derail a performance.