1.) Snap/Glare at your pianist
Be kind! They are playing your music. Be friendly without being suffocating. Sing them a bit of your song instead of snapping at them to give tempo.
2.) Use your auditor as your scene partner
Do not direct your monologue at the person auditioning you! Make sure to pick a spot above or to the side of them. Only if you are specifically instructed to do so by the auditor never, ever force the auditor to be your scene partner. They want to enjoy your performance, not feel like they have to be a part of it.
3.) Have no idea what your song/monologue is about
Read the play! Know the musical! You must be well versed on your character and what he/she wants from the person they are singing/talking to.
4.) Present inappropriate material
Make sure the character is your age and is dealing with an obstacle that you can easily relate to or have experienced yourself. Screaming, swearing and presenting especially dark material is never a good idea for your college audition.
5.) Don’t follow directions
This is probably the most important thing to keep in mind when preparing for your college audition: follow directions! If a school asks for a one-minute contemporary monologue, do not present a two-minute classical. Make sure your music is clearly marked with tempo, stop and starts and what you want them to play.