Newsflash: You have an ego.
And this ego acts like my namesake from Othello: Jago. The one who appears to be your closest friend, but is in fact your biggest enemy. Your ego is fueling you with thoughts like these:
"I need to succeed!"
"I need to be better!"
"No let's rephrase: I need to be the best!"
"I need to beat the competition!"
"I need to be loved!"
In short, your ego is needy, relentlessly needy - it never stops. The positive disguise for the word "ego" is "ambition", but don't be fooled. The ego is only in it for the sake of the ego - it's completely narcistic. Because truly, who do you need to best? And why do you need to be loved? Turn those things around: you don't need to best the other and don't have to be needy of someone else to love you! Don't fret about what others are doing to you, but what you can do for them!
It's the same with presenting. We always start from our ego: "Let me think.. What am I going to say?". Wrong! "What does my audience need to hear?" should be your starting point. You are merely presenting to facilitate your audience, not for soothing your ego. When it comes to presenting your ego will always want to take the spotlight, will want to show them how good you are at what you do, will want to rub under the nose of every member in the audience: "I know more than you!". Yes, you probably do know a lot. Yes, you probably are good at what you do and yes, that is why you were asked to stand on that stage - but that is all irrelevant. The only purpose for you standing there is to tell what your audience needs to hear.
So stop thinking with your ego and start focusing on your audience - you and them will benefit greatly from it.