Something I found incredibly helpful was to stop hiding it. Whenever I speak to people I don't know and the inevitable block comes, I usually stop, force myself to smile (it helps) and say something along the lines of "sorry, I have a stutter" and continue. 9/10 times people go "oh, don't worry" and let me finish. As a bonus effect, the cat is now out of the bag, which in turn makes me relax a little more, which again leads to less stuttering. I know everyone has different experiences, what works and not, but the above is something that works for me.