Prepare your song(s) two ways: 1) work out the problem spots, and apply technique to those and 2) practice performing the songs with appropriate facial expressions and gestures which add to rather than detract from the performance. Seek others’ opinions, from those who have audition experience and who have your best interests at heart.
Some venues expect professional head shots and resumes. There are classes having to do with this at some local (Orlando, Florida) acting and modeling class establishments such as Lisa Maille.
I once had a booking agent who told me that the fastest way to get somewhere is to look like you have already been there. Part of image is looking and acting like a professional. Seek out and observe role models such as Tom Hanks currently or Gloria Estefan or groups or individuals with manners, morals, and ethics.
AT THE AUDITION, conduct yourself with manners and respect for others. Stay positive. Don’t think about any problems and don’t let others’ problems become yours. Pay attention, stay focused and do the best you can. Thank the appropriate people for letting you audition.
We can go over more about auditioning at voice lessons. Just ask.