I've never done anything like this before, but I just scheduled a session with a speaking coach (with an astro/environmentalist background, so they're a great match for my talk).
This UN talk is only 10 minutes (+ panel discussion), but if I have to fly all the way to freaking Milan to talk in-person to a bunch of space agency heads and politicians about why megaconstellations are terrible, I'm going to make sure I do a damn good job of it.