Take up meditation! This is the single best tip I can offer you. Meditation is the gateway into you learning how to begin controlling (aka working out) your mind. Start it, it’s like doing mental pushups. Your mind will strengthen and you’ll learn to calm yourself down. This, in my opinion, is a better long term solution for you than anything else. I beat my own stutter, overcoming a 20 year struggle, and recently created a YouTube channel to share tips and tricks that helped me.