One of the biggest things with stuttering is the breath. Whenever I get blocked up to a point, I just stop and take a deep breath. I know it's one of the most common things that we are told, but it's really true. Regulating breath is key to overcoming stuttering because its precisely one of the ways it causes you to trip over your words. I once made a small booklet for myself with words that have letters, sounds, syllables that I especially struggle with. I made it a habit to read the list of words out loud in the morning before I start my day while focusing on breathing. I found some improvement this way. Best wishes for you!