Some people claim to really love presenting. (I don't believe some of them.) For most of my life I hated it, because I found myself moments before I would have to speak with a racing heartbeat, a mouth devoid of moisture that would make distracting sounds when I opened it to talk, and an almost total inability to breathe.
If any of that sounds familiar, I'm sorry. Your brain and body have positioned your audience as potential threats and have prepared you to either fight them or run in panic from the room. Since you shouldn't do either of these things, some adjustments are in order. I should mention that while I have become a fairly good presenter, I am not in the (surprisingly large) group of world-class speakers who share their advice about great presentations online. What I am is a paralyzingly anxious presenter, who has discovered some tricks that make my presentations less stressful for me and more engaging for my listeners, most of whom have no idea that I'm fighting the urge to run away. Hopefully some of these will help you if you are in a similar position.
The absolute most important thing you can do to reduce your anxiety is to know your material, inside and out. Don't try to memorize a speech; instead, you want to know the subject of your presentation, the substance of your talking points. Your goal is to be able to say to yourself, just before you begin, that you know what you are talking about and that you are the best person in the moment to deliver the content you are about to deliver.
The best way to know whether you are prepared is to practice your talk, which I do in the car in the days before I am to present. Here again, you aren't trying to memorize it; in fact, you should change your delivery each time to ensure that you are delivering information, not just words. When I take a thoughtful approach to acquiring the knowledge I've been asked to impart, and organize it mentally so that it is available when I need it, I find I reduce my anxiety enormously and divert my mental focus away from my anxiety and onto the material.
If you get cotton mouth--your mouth is dry and sticky, your tongue feels huge, and you would give anything at all for a glass of water--try drinking plenty of water (not coffee!) in advance of your presentation. If you have to start your talk by drinking then you have waited far too long to hydrate, and you will make yourself even more nervous when you start wondering if everyone can see your hand shaking.
About five minutes before I have to talk--before I start to get nervous about talking, in other words--I start consciously breathing slowly and deeply, and continue doing this until I begin to speak. This serves two purposes: first, it calms me down, and I find my level of anxiety is much lower when it is time to begin speaking. Second, it ensures I have plenty of oxygen available to get me through the first minute or so of my talk, when my breathing would otherwise be a rapid, scary distraction. There are lots of resources online with specific breathing techniques to reduce anxiety that you should check out as well.
Knowing your information is really important--knowing your data, not so much. However, you will feel more prepared if you have all the data backing up your assertions, and/or the sources from which you drew your information, available to you when you speak. Even if no one asks you for these, knowing that your assertions are sourced and supportable with information at hand will give you more confidence in them, which is always a good thing.
One way to take the pressure off yourself at the very beginning is to ask a question to get people to respond. "How many people have been to [place you're talking about]?" "Did you visit the [subject of your talk]?" Asking questions keeps the audience engaged, which keeps them on your side. It also gives you a feel for the energy level of the room. When done at the beginning of your talk, it allows you to start without starting--giving you those first few seconds to keep breathing and establish your focus so that you can start your talk more relaxed and comfortable.
If you are interested in your subject it will show, and it will allow you to be engaged with your material instead of being self-absorbed and performative. Your listeners are looking to you to give them cues about how to react to the material you're presenting. If your energy is low and you're mumbling your way through data with your eyes fixed on the clock, you're telling them your information is not important and they can browse the internet for the next ten minutes. By being more animated, making eye contact, and pointing out items of particular interest in your talk, you keep up your side of the feedback loop and will be rewarded with positive interactions, which in turn will keep you relaxed.
I'll close with a word on this advice that people always seem to give people who struggle with public speaking. The reasoning goes like this: if you're intimidated by a group of people, make them seem less intimidating, which will give you more confidence. One problem with this and similar approaches is that they require you to focus on the audience, which is the one thing you're trying to avoid. Also, it would be good to have respect for and feel honored by the time and attention of your listeners, which is difficult to do while you are playing the Naked Audience game. I think the strategies I've mentioned work for me because they redirect my focus away from the audience and onto the material being presented, while taking concrete steps to prepare both physically and mentally for presenting. This seems better to me than trying to prop up your self-image by diminishing your listeners.