Here's one thing that is a little different about speaking in front of large audiences. The difference is, you need a little more of a pause between your big thoughts. It takes a while for your sound, to simply travel all the way around a large room, regardless of the number of speakers, and there occasionally could be an echo, you help yourself by having a little more of a pause between your thoughts a little more of a transition, and allows the sound to filter out through the room and allows people to process it. Part of it is they can't see your lips and your mouth, as well as if it were just a room of 20 people speaking, there are fewer visual cues although there may be a big image magnification, still, you'll make it easier for people easier to digest. If Pause a little longer between thoughts between paragraphs.

And if you just speak a little bit slower than usual, it's just easier for your words to flow through the room or through the audience. So keep that in mind with the speed, especially given that you might be nervous and when we're nervous, we tend to speak faster than usual. So slow it down. More pauses