I've been a gym owner/operator for 20+ years.
Sales, promotion, service, administration (back office), expense control and attrition control is what I would focus on to impress them.
Sales and team building: Driving new members into the club. Getting your existing members to refer people to the club. This is a refer and duplication business. Build a strong sales team that believes in fitness.
Promotion: Print or other advertising, gorilla marketing, community outreach.
Administration: Making sure the back office is properly handling members accounts, setting up the correct billing and collecting past due members.
Expense Control: Running lean payroll, but not sacrificing quality service. Keep supply ordering in check, lights, HVAC etc. Anything that you can do to keep expenses under control. Budgets are a must!
Attrition Control: This is the key! You need to understand how many members you are losing each month. If you losing more than you are bringing in, you are going backwards on you monthly dues EFT. To many operators do not pay enough attention to this. If you can get a handle on this, making the business grow or maintain will be much easier. 3-5% total attrition a month is desirable.
Keys to keeping attrition under control:
High service and a great staff
Proper EFT billing
Back office collection of past due members
Cancel saving members who come into cancel
Study this and I bet you will get the job.