Practice doing presentations in front of your family or a group of friends. Try using a microphone as well if you can. Practice in front of a mirror as well and you could even video record yourself doing a presentation so you know what you need to work on. You really just have to practice.
Take your time when doing it. NEVER try to rush through it. Take deep breaths every couple of sentences so you don't stumble over yourself. And smile: you tend to emulate a certain charisma when youre smiling, and people are more inclined to listen to you.
Finding a focal point to look at also helps. When actually giving your presentation find somewhere to look and then it will become easier and you will be able to look around and make connections as well as lose a bit of nerves
go talk to random ppl u don't know in the street