I have been VERY nervous about public speaking when I was younger, forgot what to say often or got very hasty so I spoke so quick that some words came out wrong. It got better over time, slowly. Sometimes I am still quite nervous about it, but I seem to have developed something that sometimes I am able to get into some kind of self-absorbed stance (I have no better name for it). I get detached from all external influences and am fully concentrated on the topic I am talking about, and things come from alone. I don't panic anymore, I am very calm and just say what I have to say.
I cannot say how I get into this stance, I don't always get into it either. I think it depends mostly on how competent you feel on that topic; if you are not really secure about what you want to say, it is harder, but if you know very well what you have to say, then it is easier. Maybe it also depends on how many people there are actually in the room. I can experience this stance sometimes in a more extreme way when being alone, when I am daydreaming - I get so self-absorbed I totally forget about things around me, and sometimes it goes so far that I suddenly have to get aware of my own physical existence again actually.
My best presentation was that of my oral exam for my school graduation. I could experience such a stance, and I was totally free of any worries. I was so into the whole topic I forgot any consciousness about time, but still I was perfect in time. I didn't even take notice of the teachers in the room, I just talked, slowly but clearly. The thing is I don't really interact with the audience when doing so, don't even look at them but rather have my eyes half-closed and looking somewhere lower, and I think it doesn't work very well when interacting with audiences. Nevertheless I made apparently a good job since teachers were really impressed, and I got the best possible grade (15 points). Teacher said he would even give me 16 points if he could
So I don't know if I can give you much tips for yourself about it. I would say try to be fully concentrated on your topic, try to not interact much with the audience, try to ignore any external influences. Of course that is not so easy when you have to interact with your audience, because they can ask questions or so. The best would be then I think to not letting yourself being interupted, but make them wait for some time until you finished that part of your speech before you answer questions, and then go on again. And of course, practicing it will help improve your confidence with that process. Important is also that the words you say come directly from your inner, so they feel natural to you, rather than just saying something you had learned by heart (a stupid saying actually, because learning by heart means anything but that it comes from your heart). That requires obviously that you know all coherences and relationships of things you explain. You can take notes for yourself, but should hold them imho as short as possible, maybe even single words sometimes, so you know what you have to talk about, but have to formulate things yourself still.