Be prepared to demo a class. I never hire an instructor from resume' or application only. Even presenting a video resume is a creative idea to differentiate yourself and "audition" all at once. You will be asked why you love the industry, how you came to be an instructor, and what you hope this position will lead to. DO NOT say "I want to get paid to work out." This self serving statement is indicative of a "diva" personality and will not land you the job. Truly wanting to help others is necessary in this field.