Practise is key. Constant practise. Within the approximate timeframe of how long your presentation should be, record yourself with a timer on your phone and keep practising the words until you memorize some of them and until the practise becomes muscle memory. If you find yourself talking better when speaking alone, use that opportunity. Use a bit of hand gestures to guide your voice out. Even if practising may take hours, do it. But don’t forget to take breaks and especially some sleep to preserve your energy. If you’re worried about getting a mind blank, type out the bullet points of your speech in a small Google Doc/Note/Word, etc. file on your phone to bring it with you just in case for your presentation. Although recommended to speak when making eye contact with your audience, you can stare at your slides if you’re feeling nervous. But try to small glances with your audience when you can.