I have no experience, but I'm studying speech therapy, so I heard stuff from my professor and from stutterers. One of the best techniques is probably the pull out, taught in stuttering modification concepts, like van riper or IMS (might be limited to the German speech therapy, but there are a lot of similar concepts). Pull out means,that you stop speaking when the Symptom hits wait 3 seconds and then you speak the word in a slow soft way. But it's very difficult. Easier are techniques like prolonging (in German prolongieren IDK the English word) or soft voice (weicher stimmeinsatz in German). They are part of fluency shaping. That means that you modify your speech in words that might be stutterd. It's definitely much easier if you try to learn that in therapy tho.