Everyone is different. Some people just get used to it and stop caring, for others it naturally lessens. The majority of people who used to stutter and are now mostly fluent didn't do anything magical. I'd be willing to bet most didn't do anything at all, except maybe talk more. Also there's no such thing as cured. Even people who don't have trouble with stuttering anymore are still stutterers, they just stutter very seldom. Stuttering is an innate part of you and you can't eliminate parts of who you are.