It mostly boils down to what kind of attitude you bring to it, however. Even though preparation is heavily important too, no amount of it can save you if it doesn’t also come with the outlook and disposition that will allow you to carry things through and maneuver through them regardless of what happens.
There may be plenty at stake when presenting in front of a high number of people. But our worries can make it worse than it has to be. And past a certain number, when it breaks beyond what makes it something within one’s initial comfort zone, the numbers begin mattering less unless you fixate on them.
There’s a crowd containing numerous people, there’s it being broadcast live, there’s being recorded and saved to be replayed for years to come, there’s the rating and commentary it could receive, there’s how it does in terms of what the aim is and how much it was invested for it, there’s your own standards for how you perform and make the best of it, and more. All of this could crush your spirits if you let it.
If you’re the main attraction, much responsibility falls on you. It tends to be lighter when you’re one of many, a backup, or an extra to it. Depending on where that puts you. But whatever the case, it helps to remember that no matter how spectacular people can be, people are still human and things happen. Rarely does anything go exactly according to plan or how it is ideally envisioned. Your job is to take it seriously enough to do it at least close to your best but not so seriously that you’ll trip over yourself and have a nervous breakdown because of it.
As for how to go about it, more specifically, you must find what works for you and/or the type of presentation that you’re doing. Maybe it is being exalted and amicable, or maybe it is being in your own bubble and aloof. Or anything in between, mixing it up or interchanging it as it suits it.
Addressing a wide crowd doesn’t have to be always general and vague either. You can identify what everyone or the most amount of people attending and viewing you have in common and focus on that when speaking out, but you can also take moments to address subgroups within the entire group, choosing your words to call out to them. You may even single out particular people if it is appropriate and worthwhile.
Nevertheless, even though what you do determines much, there is indeed such a thing as an awesome crowd to be genuinely amazed by and thankful to. People who are glad to be there and return the same energy or even multiply it. As opposed to people who are predisposed to not have a good time and belittle all efforts. If the latter, don’t take it too personally. Though see what you can do to not repeat such situations too often. Perhaps measures can be taken and accomodations can be made to enable others to be their better selves while there, too.
And remember, you get better with practice. Allow yourself to have shortcomings and make mistakes, knowing that they will be less and less as you go on and set yourself up for the best.