From Back Stage
The best way to get ready mentally for an audition is to go in as prepared as possible. “Make a professional-level commitment to your craft,” says Karen Kohlhaas, New York–based director, author, teacher, and co-founder of the Atlantic Theater Company. “Practice treating every audition, rehearsal, or scene you do for a class like it is a professional job. The more work you put in, the more you will feel you deserve to be there, and to be seen and heard by your auditors and audiences.”
Read more on The Psychology of Auditioning.