What helped me a lot in university presentations was practicing what I was going to say at least six times so when I get up there, I know exactly what to say. Also, controlling anxiety before I went up to present was huge. The trick was to control my heart rate and breathing. Don't drink coffee or energy drinks, make sure you are well rested, and practice controlled breathing. I alternated between breathing in deeply through my nose and exhaling fully through my mouth, and holding one nostril closed and only breathing in and out through the one open nostril. The latter technique forces you to slow your breathing because only so much air can go in and out of one nostril. Controlling anxiety was probably the hardest part, but it will drastically improve your fluency. In addition to those things, simple experience helps a lot too. When I did my first presentations in university I was always nervous and stuttered more often. By my senior year (and many presentations later) I was fairly confident and good at it. Sure, I still stuttered now and then, but I found it easier to embrace it than be ashamed by it. They are going to see my stutter anyway, may as well keep my chin up while I do it.