What a beautiful place (and virtual tour)! Gorgeous. Congratulations. From your ad, it looks like you already know what to do since it's very enticing. We use Beach Rentals of South Walton and we are happy with them as an agency. Their cleaning is quite good and they stay on top of the maintenance. But other people on this site have experience with them and others. I switched agencies from one to them because the cleaning wasn't very good at the other agency and I think the biggest turnoff to guests is walking into something that isn't really clean. Also, I think it's important to build a relationship with the people at the agency. Even though they manage your property, it's a partnership that is invested in making the guests happy and your property a success. I like VRBO (Vacation Rental By Owner) -- I get 2/3 of my rentals (or so) through them, the rest through the agency (but the agency manages them all).
I hope this is helpful. There are other threads that focus on rentals as well and you can get a lot of specific rental advice on those, too.
Congratulations on your wonderful place. It really is gorgeous.
and congratulations!!!!!!