Every person who stutters is different. It is fairly common for a PWS to be fluent when alone in a room, talking to pets, babies, young children (Lewis Carroll for example). One of the best ways to enhance fluency is to learn fluency shaping or stuttering modification strategies from a licensed speech therapist. Once you are able to use these strategies alone or in the therapy room you have to use them in the real world. In class, with family, is stores, etc. More easily said than done of course. (Sauce: I am a PWS and licensed speech-language pathologist)