One of the best ideas I ever implemented for my massage business was a referral program.
I offered a "refer 3 friends, get a free massage" program. I put a sign up in my massage room, as well as placed around my studio. Signs like "want a free massage? Ask me how!"
I was amazed at the response. I got a lot of new clients from this program. But actually ended up giving away only a handful of massages. Very few times did 3 new people come from 1 client.
I definitely recommend having an organized way of tracking your referrals. It can be as simple as index cards in a recipe box. Have a card for each client who has referred to you, and list the clients they have referred. After 3 (or however many you decide to make it) - offer them their free massage and mark it on their card when they received that massage.
*Shameless Plug: if you use Bodywork Buddy, there's a referral tracking feature built in. When a new client comes in, you can record who referred them. Then look up a client file at any time to see how many people they have referred.
Do you have a referral program? How has it helped your massage business?