Rehearse as much as you can. Know what words are harder than others and try to predict when you're going to stutter so you can pronounce those words softer and take a breath or pause beforehand. I find projecting your voice helps, as well. You can do it, preparation is key and I know it might be hard but try your best to relax the night before. Get a good nights sleep, that will make a huge difference, drink plenty of water and tell yourself that you can do it. Best of luck, you're going to do great.