What can we possibly do to never loose a Guest?

Keep a constant communication insisting on feedback, upcoming tours/events,by all means and keeping them informed concerning the updates and new offerings of your total product or services. 

If they don't need to use your  service at the moment,try to offer them other assistance for their current activity in other destination.

We should try to exceed the expectation of our guest with every interaction.

in simple words:-

1- Recognition

2- Continues upgrade

3- True Discounts

why should i go anywhere else as a guest while i am here like an owner of the place??