Anyone have tips on how to be a good actress?

I have signed up for a television audition. The audition is only in about a month! The judges are going to give me a script that I have to read AT the audition, so I have NO IDEA what to be prepared for! I need some tips on how to ACE the audition so I can be on television! Also, I would like to know how to seem professional... I already know I have to dress up for the audition!