Get some photos of your studio/work place Fitness Marketing Idea, you in action training clients, some individual client photos (to make sure every existing client has a photo on your page), a group photo of all your clients (be sure to tag them all) and a nice professional shot of yourself and add them to your fan page.
Get some videos of you in action, client testimonials at least 3, before and after pics and a video profile of you your qualifications and your services you have to offer.
(Remember to get a whole heap of written testimonials as well).