Find a place (Upwork, craigslist, etc) where your customers are talking or posting that they need a service that you provide. Use IFTTT and create an alert when a new post is made. Use Zapier to move the data into google sheets and set up an email autoresponder with a message like "Hi. I have a ____ expert available in your area that has availability in the next week." Then just give them instructions on how to sign up. Almost no cost to connect with people who have a specific need for your service.