In my experience, even though it works from time to time for me, speaking mindlessly occasionally helps me with my stutter. When I say mindlessly, I mean just blurting out what you want to say, without thinking on what other people might think. Overthinking things before speaking doesn’t really help, since normally in my case it generates more anxiety that adds up to the stuttering. Another helpful belief towards stuttering might be accepting that you stutter and take your time speaking, since in my experience most people don’t really care about your speech impediment, since they usually get used to it. Accepting it is easier said than done, unfortunately.