IMO Practice your full speech in the mirror by yourself. Look at your self in your eyes to build confidence, then look at your mouth to detect any slip ups. Next practice your speech in front of your family and people you do not stutter around. Ask for their feedback on how your speech is. Next practice your speech with a random person or someone who you would stutter in front of. The goal is to find out what are you doing or feeling differently when you Sutter vs when you don't and work on them. If you say when you think about it then I would recommend to work on your confidence when you speak. Not only for public presentations, but Overall confidence everytime you speak. You got this! I hope this helps.