I was a shy kid who would avoid public speaking at all cost
My English was bad, and I had a huge Chinese accent. Public speaking was not my thing at all.
During my last two years of high school, everything changed.
I joined the debate club, Model UN, and DECA, all of which requires both strategy and presentation skills.
Practice presenting it to your friends
Do 15-30 second elevator pitches to your friends to get feedback but also, strengthen your presentation through repeated practice. You might find new points to talk about along the way.
Research your judges
Find out what industry they're from, make references to topics that they seem interested in when presenting your product. You'll get their attention easier.
Think of potential questions that judges would ask you
Ask for feedbacks from your friends or evaluate your idea yourself. Do you have the answers to the potential questions that they'll ask you? This is key.
Eye contact and hand gestures
Maintain warm eye contact (no intense staring) with your judges. Use hand motions to direct their attention yourself or your powerpoint. Don't over do the hand gestures though.
If you feel that you need to say "ummm..." replace it with a short pause. It makes it seem like you're formulating a better thought rather than just lost and confused.
Graphs and visuals
Judges won't have time to look through your graphs, but it will grab their attention. The numbers make them curious, so make it rain with more details about the numbers in the graph.
Longer doesn't mean better
Don't stretch your presentation out with 20 points and slides with minimal information. Condense it into fewer slides that have more important details.
Make short pauses before switching slide/point
Let the judges absorb what you just said. They're writing down notes and listening at the same time. Make it clear that you're moving onto a new and important point.
Smile for the camera
Maintaining a happy expression shows that you're confident in what you're presenting. If you're confident about it, chances are, the judges will believe in it more.
Hope it helps!
These tips got me through a number of presentations, and they are what I looked for when I was a judge as well. Good luck!