https://www.stutteringhelp.org/Portals/English/book0012_11th_ed.pdf I’d highly recommend having a read of self help for the stutterer by Malcolm Fraser, really helped me. Found the bits that deal with the psychological aspect of stuttering most helpful. Personally I’ve found the main thing for me has been overcoming the negative thoughts and feelings that surround my speech has the most important thing. With gaining a degree of acceptance I don’t go into speaking situations with the degree of fear and anxiety I once did which in turn has led to my speech improving significantly. A lot of what causes us to stuttering is what we do trying not to stutter, we basically play nasty trick on ourselves without meaning to. I guess what I’m trying to say the less you care about it and less you think about not stuttering the less you will if that makes sense.