A person is hired after auditioning because she stood out from the hundreds of other girls auditioning for the part. It is the same for belly dancing. You may know the steps mechanically, but it's important to dig deeper and really feel the dance from your heart. Let the dance moves move you and others watching you.
Have an exact copy of the music you will be using for your audition so your practice involves the same movements you'll dance. Listen to the music in your car, at home, while brushing your teeth or whenever. Memorize it. Picture your movements with the music and practice as often as possible until you feel so comfortable with the moves, you could do them in your sleep.
When choreographing your dance for the audition, be sure to transition moves creatively yet smoothly so the moves feel seamless. For example, if you move your hips around, bring your hips back to the center before beginning the next movement. Another example is to bring your arms equally in front of you after having one arm up and another arm to the side, and then bring your arms into the next move.
Your entire audition should be captivating, but the beginning and end are most remembered. A strong beginning captures the panel's attention so they want to continue watching the performance. A strong finish makes a lasting impression of beauty and confidence. Keep your emotions clear and confident. Show the panel just how much you enjoy belly dancing.