Have clients sign a contract with your terms explicitly laid out and also get a verbal confirmation from them.
You can allow grace periods; perhaps someone who cancels last minute can make it up later that week without charge but beyond that decide whether the session is lost. It minimises clients who try to take advantage of your time.
But that said also let your coaching side come forward! A simple but kindly worded text or a voice message or call that always gives the client the benefit of the doubt can be an invaluable part of forging a meaningful working relationship.
Never transmit any sense of indignation, frustration or anger. Instead, assume the reason for the cancellation was always a serious one and ask yourself how you would word your message if your client had suffered an accident or had had a serious illness in the family? Use that TONE and let the client share as much or little as she wants.
Usually the reason for cancellation will not be that dramatic but the client will appreciate your caring and lack of judging.
They will typically feel a bit guilty that you are taking things seriously while being so gracious and, more likely than not, they will rise up to your level of commitment.
What’s your take handling client no-shows?