Mine was Air Force, and also a while ago, but I just remember practicing saying my name and the airman's creed over and over again. That and stuff like "YES SIR/MAAM", "NO SIR/MAAM", and other basic answers helped a lot. Beyond that, I think my stutter actually helped me out a bit? I was used to keeping my mouth shut to avoid sounding stupid, so there was a lot less opportunity for me to say something dumb and get smoked out.