I think the best solution for us is treating the anxiety more than the stutter itself. For example, after a good gym session my anxiety decreases to a level I can speak without any block for a while. Many people mention meditation too to manage anxiety but I didn't find it to make so much for me. Remembering to speak slowly before starting a speech or phone call is used to help too. Take a look at the Camperdown method to practice to speak slowly.