Preventing patient no-shows has challenged medical offices since the invention of the appointment book. Some practices have gone so far as to charge patients a cancellation fee. Though that clearly communicates how seriously you view not showing up, you'll likely collect more hard feelings than revenues.
Consider a reminder system for routine follow-up and well-visits. Postcards mailed to patients a week before each appointment consistently reduce missed appointments.
When staffers go the next step and make personal phone calls one or two days before office visits, you'll usually see a still more dramatic decrease in no-shows.