1. Advertisements, leaflets and the like, let everyone know that you exist.
2. Local network, send some knowledge about fitness to your local website forum, and send you preferential price conditions for the overall facilities of the gym.
Write some articles about fitness and health, and publish them in local magazines, newspapers and the Internet.
The first three items shall not be for profit. They are committed to helping everyone. The initial effect may be small, but the effect of slowly gathering is great. You have to pay to get a reward!