Memorize your presentation, dont read it slide for slide. It might give you more confidence knowing whats there instead of having an idea of whats there if that makes sense. walk around ,fidget with your hands, using your hands to talk. Fuck it by a fidget spinner. Use your techniques. You could prolly start off by saying you have a stutter. At least for me Im more insecure about my stutter with those who dont know i stutter. Go at your pace. They HAVE to be there. Whether you finish in 30 or 45 minutes they are gonna be there. This is definitely a hurdle for someone who stutters. Either get over the wall or stand there staring wishing you did.