Get a good teacher. A good teacher can help you improve your technique, musicianship, and stage presence. They can also give you valuable advice on how to prepare for an audition.
Perform as much as you can. The more you perform, the more comfortable you will become on stage. This will help you to give a more confident and polished performance at your audition.
Network with musicians and conductors. Attend concerts, join musical organizations, and talk to people who work in the music industry. The more people you know, the more likely you are to hear about opportunities to perform.
Prepare a great audition. Your audition is your chance to show the judges what you can do. Make sure you have a well-prepared program that showcases your best skills. Dress professionally and arrive on time for your audition.
Be persistent. It may take several years of hard work and dedication before you are accepted to perform at Carnegie Hall. Don't give up if you don't get accepted the first time. Just keep practicing and performing, and eventually you will achieve your goal.