Listen, I know you are busy and that you are stacked out with queues of patients and potential new patients.
However, no matter how busy, you have to keep filling that reservoir of goodwill with your existing patients.
By keeping them well informed of what's going on in the practice, by looking after them as if they were your family and - here's the important bit - by explaining that you are always looking for referrals from their family, friends and colleagues.
Having a waiting list doesn't mean that you are closed to new business - it means that demand is high and that you are a preferred provider.
On waiting lists - take a leaf out of the book of Disneyland - keep the members of the queue very well informed as to what their waiting time will be.
"If you are standing here, you will be on the ride in 35 minutes."
So that they can make an informed choice as to whether they want to stick around.
If they do leave - that's OK - they will either get what they need somewhere else or (more likely at the moment) return later to say the other "rides" were either closed or had bigger queues.
On marketing - the absolute bare minimum:
Your email patient newsletter every month;
Your constant requests for Facebook/Google reviews;
Your responsible use of social media to share patient and team stories.
Please don't fall into the trap of thinking that you don't need to do any marketing because you are so busy.
Plan ahead. Dig the well.