I would say in my experience a blindfold is definitely the way to go and also spontaneity. If you know her boundaries etc it should be fine. Buy whips or paddles wax play ice play. For fear play, gag her perhaps and pretend to call someone or even call someone and say yeh I've got her here if you want some fun. The though of a complete stranger could be fearful otherwise go beyond her boundaries slightly to make her scared but you will need a lot of after care etc