How can you improve your speaking in public?

By doing it, practicing it. I would say: first practice talking in public about topics that you love and that you know a lot about. People should see your eyes sparkling and should feel your passion for what you do.

Also try to get dressed up in something you like and something that suits you well, it will make you feel more confident to speak in public.

Try to speak with the tought: if I speak now, I can gain this and that. I have nothing to lose, it's now or never. These are humans just like me and most of the times they don't even pay that much attention honestly :D especially during presentations.

Good luck :)

you have to be bold an audible