This is probably not a sustainable way if you have to do public speaking on a regular basis/have to do it on the fly, but what has worked for me throughout university was to prepare scripts that "flowed" better (i.e word replacements, rephrasing, that sort of stuff). Having a better "flow" when you do execute the speech would greatly increase your confidence right there and then, and for the most part, I didn't feel like I had a stutter at all. Doesn't work for impromptu speeches of course...