A lot of good ideas here. In the past I have come right out and told my current clients that I would really like to be busier. I ask them if they would want some of my business cards to give to people that they think I could help. If they agree to do this, I give them a free session on the spot saying “This is my way of saying thank you. Not just for your trying to help me, but for believing in me enough to try and help me.” Not only has it worked well, but sometimes the client opens up a bit more and I can help them even better than before the request. I think it helps build rapport and deepens the connection with the client to help each other in even small ways.
Please get back to me if you would like to correspond on any fitness topic. I enjoy connecting with others in the fitness field.