Today’s the day. You have a presentation to give. It’s your biggest audience yet. The organizers tell you there could be as many as five hundred people in the room. You can’t afford to screw up now.

What thoughts run through your mind? Will I screw up? Will it go well? What if the technology fails? What if the audience gets bored? What if they don’t laugh at my jokes? What if someone asks me a question I can’t answer? What if? What if?

Most people find these preshow jitters distinctly unpleasant, and they won’t be happy again until the speech is history and they’re relaxing with a drink at the bar.

Some people fare worse; they are so debilitated by fear that if they ever get this far, they’re probably vomiting in the sink by now.

A lucky few actually enjoy the experience, using the butterflies to bring them to peak performance during the presentation and reveling in the excitement of working with a receptive audience.

How can you get there? And what are the other tricks that will help you give your best presentation ever the next time you’re up?

You need to focus on both sides of the adrenaline equation from the beginning, and now is the time to do it. Both your mind and body are involved in creating the circle—either vicious or virtuous—that creates adrenaline, and both need to be involved in controlling and channeling it.

So start by creating a picture of yourself giving a splendid speech. Make it as detailed as you can. Replay it a couple of times in your mind, until it’s clear and precise. You cannot possibly do this exercise well if you haven’t visited the venue and, at the very least, stood in the space you will occupy later, imagining yourself speaking to a packed house.

So I’m going to assume you’ve already done that. Ideally, you’ve already rehearsed the speech in the space, so you’ve got some good, specific sensory memories to draw upon.

Then, once the virtuous circle of positive thinking is initiated, treat the body just as well. Breathe properly, and undertake a mild workout, especially using muscles that you know tend to tense up for you. The idea is not to exhaust yourself; that would be counterproductive. Rather, keep yourself from getting too agitated because of the unusual amounts of energy your adrenaline is providing you.

If you’re stuck for ideas, simply flexing and relaxing your major muscle groups should help. A brisk walk is also a good idea; spend the time going through the presentation in your mind, successfully, of course.

You will want to develop a good lifetime habit of warming up the voice every morning, or at the very least before each presentation. The best warm-up is the one singers use. If you’re not a singer, then find a few songs that you’re fond of and that are comfortably in your range, and warm up in the shower or the hotel room by breathing carefully and singing those favorite songs gently with lots of breath control and sustained pitches. Try to pick upbeat, cheerful songs.

Water, of course, is the preferred drink of speakers. Everything else is second best or worse.

Are you still feeling nervous? A little nervousness is actually a good thing. Too much is debilitating. The positive imagery should help. Just invoke that every time the nerves flare up.

Also, this is a good time to review the speech once again. Don’t give the whole thing; it’s too late for that and will only make you stale. Instead, go through the outline of the talk in your mind, so that you know exactly where you’re going and what you’re covering at every step of the way.

Once you’ve warmed up and performed the mental and physical gymnastics it takes to get yourself in peak form, go to the room. Preferably before the crowds are there.

Begin at the front of the room, where you’ll start talking. Take a deep breath and look around. Focus on the three walls to the left, right, and front of you. How far away are they? How tall are they? How are they lit? Can you see clearly, or does a twilight gloom invade the corners?

Now look behind you. How close is the back wall? What’s on it? Anything that could possibly distract an audience? Anything that looks more interesting than you?

Fix the room in your memory, its height, lighting, size, distant boundaries—the works. Then walk it. Walk the entire perimeter, stopping regularly to look back at where you began. How far away is that speaker? How hard is it to see where you’ll be? Anything blocking the audience’s line of sight?

The idea is to get a sense of how large the room is, and thus how hard you have to work to reach everyone in the audience. Most speakers talk to the front few rows. They have neither the volume nor the energy to reach the folks in the back.

Once you’ve walked the room, then you’re ready. Keep breathing, keep running your positive mental script, and keep the first few lines of your presentation in mind. You’re ready to go.