Hi @John91,
You cannot give any insentives for reviews.
Instead make sure the guest has a nice comfortable stay and be available whenever required, make sure your house is cleaned before guests arrive, you can offer some fresh fruits or any local specialities which aren't too expecsive if you fish, guide them well, give a house tour, help them with the addresses, nearby attractions, activities.
In short, be nice and you'll definitely receive a nice review.
Good luck 🙂
I hope you have a wonderful experience with your first guest.
Jeet