How do you avoid making a bad impression when delivering a presentation? In my experience, people worry about this a lot, but they're worrying about the wrong things. They're worried about, oh my gosh, I moved my hands or I said two arms. Or I forgot something. I didn't get something in the right order. Those are not things that the typical AUDIENCE MEMBER notices or cares about.

The far bigger problem, the more common problem is is not saying anything interesting, not saying anything memorable, getting up there, and it's just why Wow, I just too boring data dump. The biggest problem most of us have, is we wasted the audience's time by not saying anything interesting and memorable. If you're interesting, memorable and useful to the audience. They'll love you and they'll also forgive any other little flaws.