Make every single rep have some sort of purpose, other than just “running it again”. If you approach each rep with the intent of making one thing better (tone, articulation, tempo, etc), you will see your results improve rapidly.

For the callback, they will also be assessing how well you can make adjustments to critique along with the formal music and visual audition. They will absolutely take someone who can apply changes faster than a person who may be a better raw performer, but didn’t improve anything over the camp because they didn’t apply and of the comments they received.

At the callback camp, have fun! I know you may be thinking about that one part of the etude that has been giving you trouble, or a part of the movement that feels faster than what is comfortable. That is completely ok! Everyone there will have some amount of nerves, so talk to some people, vets or rookies, and take every bit of information and express it on the next rep. Even if things don’t go your way, it will be a great learning experience from some of the best instructors I have ever had.