She came in – breezed in, rather – looking perfect, resembling Kareena Kapoor whether she is aware of it or not, eyebrows up, regarding without interest the mere mortals before her, who have come to ogle at her and pretend to listen to her.
Oops! Mistake #1. People may admire you while you speak but that is not why they waste their time and attend your sessions. Well, not always. So you might as well show a little humility.

And when she spoke, Mistakes #2 to #10 followed.

“I don’t know” is not an unacceptable answer when it is followed by “I am sorry, I will check and get back to you” or something to that effect. It is not “I-don’t-know-so-it-is-a-foolish-question”.

One does not mock a person for asking a question, however dumb it sounds. Give it due seriousness and clarify the answer as best you can. I remember once in a session related to Y2K in 1997-98, the presenter was asked a question, “What did we do in the turn of the last century, when a similar problem might have occurred?” The answer was very, very obvious. There were no computers in the 19th century. He could have laughed out aloud. But he did not. He answered gently and appreciated that someone has thought about this. The person who asked the question perhaps realised later that it was not a very bright one, but was grateful for not being snubbed in public.

A man from the audience asked a question.
She said, “Ok, the guy here – what’s your name? – has a question…. ” Uh-oh. Doesn’t sound nice. It may be okay while in casual talk but before a crowd, such references can be avoided.

Another talk recently given by a colleague, quite a young man, comes to memory. He spoke too fast and ran through the slides so that no one could make out what he was trying to convey. Everyone left the room confused.

It would be ideal to stand before a mirror several times before presentations, – forget the topic, just imagine you are talking about anything under the sun – and talk. Imagine some queries coming your way. Pretend you are really in a conference hall and answering it. Use the same gestures you would do before the audience. See how you look when you answer.
Are you being arrogant in the way you handle queries? You can polish your expressions and keep a smile while talking.
Is there clarity in the way you put a point across? It does not hurt to repeat a point if the questioner does not look satisfied. Do not move to further slides or queries before this person is satisfied.

Another important thing to look out for is repetition of phrases. In the nervousness of standing before a lot of people, one is not conscious of what he says, so phrases tend to repeat. Perhaps a good way to identify this is to record one of your talks and play it back later.

Attitude always matters. Even if you are one hundred percent clear on the topic you handle, if you do not put it across in an amicable way, people are not going to be satisfied. And your attitude is going to make you a better presenter, more than anything else.

Remember, being a good speaker does not happen overnight, neither can it be achieved by reading a book on presentation skills. It takes a great deal of effort and trial-and-error.

Keep talking!
Good Luck!