Santorini is one of the most magical places in our planet. This is where one can get melted and mingled with the sunset itself. Everything is magical in
Santorini, from the kind people, the mazing sea view, the sunset, the volcano, till the beches that get crowded in summer but still you can find a calm place if you need to relax.
The only thing you should do is organize the main harbour. When all the ferries arrive in the morning, it looks like an african market. Also prefer smaller places to eat, probably they will take better care of you than in the busy places in Fira.
Take a tour to the volcano and I would also suggest you to take a tour to Thirassia, a small island opposite Oia where hardly twenty people live and where you can get a bit away from crowds. It is a pity that there isn't a room to stay in Thirassia, it would be so nice to spend a night there.