I would use the advertising money that you budgeted in your business plan prior to starting your service to send out some postcards. Your marketing budget should be proportional to your gross sales by a factor of four in your first year.. maybe a bit better if you are a good salesperson.
eg: If you have budgeted $5,000 you can expect a return of $20,000 in gross sales. After you pay your insurance, bonding and supplies I guess you can make about $14,000 your first year. Hopefully you budgeted more than $5k.