Preparation is the key to a successful presentation. You can join one of my courses on better presenting, but if you can't participate in that, just remember these 3 important points:
1. You are the presentation, not your slides. Keep your slides simple with as little writing as possible.
2. How you speak is important. Practise emphasising the important words, taking pauses and not speaking too fast. Videoing yourself is a great way to practise.
3. Fake it til you make it! Inside you might be a mess, but stand up straight and act like you are very confident. Even if you're not, the audience will think you are. And don't forget to smile!
Here's a great article on how make awesome presentations. Good luck!