What is your style of training?
There are certain fitness centres who specialize in certain a particular type of training, like plyometrics, Pilates or TRX, etc. But in case you do not already know that style of training, but show that you are willing to learn. As a trainer, you are required to complete a certain number of continuing education credits to keep your credential. In case you know the style of training, tell the employer about how you have used it and what successes you achieved in using it with clients.