Try focusing on opening up your throat before beginning your speech. You might even make a small sound that will help fluent speech begin. Imagine you are pushing a cart on flat ground to give it enough energy to reach the down slope just beyond the flat ground, give it enough to get there and then jump in and enjoy the effortless ride. Put melody in your speech to help fluency. Imagine yourself doing it and then do it. When you fuck up, don't beat yourself up over, say "fuck it" and move on. I think what I'm describing here is referred to as "easy on-set."