For me it gets worse when I’m stressed because I’m feeling unprepared or too anxious. So best thing is to be confident. 1. Prepare a bit the key points you want to say. Don’t try to memorise the entire speech - that’s both too difficult and you will hit a block at some point and that will ruin the preparation. 2. Convince yourself that this isn’t that important. There will be lots of other public speaking events in the future - so it’s just another opportunity to exercise. The stutter doesn’t matter for your closest friends or loved ones - so no point about caring about the rest of the world.