As I think back over the years I can remember when I had that same question. I think the best way to pick up a new paying client is to get out in front of the potential clients you want to market. If you are working at a local health club. Offer your help and guidance .Introduce yourself and let them know you are there for them if they need any help reaching their goals. Once you break the ice, not only will that give you more confident, you will also allow the potential client a direct connection with a Fitness professional. You will be surprise on how many members are watching you and want your help, they are not sure how to ask for it.
Best of luck to you, now get out there change some lives!!