If you can gain the mindset that public speaking is really no different from a conversation with a friend, then you could be well on your way to overcoming this fear.
As mentioned by others, preparation and practice are very important in order to have the confidence to step to a podium in front of an audience that may be a few or a few hundred and know that you are ready to speak. There's something very different between a speaker who has done their homework and one who hasn't. So resolve to yourself that you will be ready when your turn to speak comes and know that the work you invest will pay off in an impressive presentation.
I think it is also very helpful to envision yourself beforehand, playing out how the presentation will go. Much like how sports psychologists encourage athletes to think about themselves winning, I'd suggest you think about how it would look to deliver a speech that hits all the high points with gusto and is well-received when you finish.
Once you have that confidence and once you have that mindset it doesn't really matter how many are in the room. You will be an impactful speaker.