I might be hyper-sensitive when it comes to sessions - or I have sat through too many at this point in my life. Or maybe both.
Rule 1 when presenting: Respect the Audience!
Respect their time, their Attention (which is a precious gift) and their Intelligence.
If you have 20 minutes, end it in 15 minutes so you have time for a question. Don't run over! You disrespect the event, other speakers, the audience and my attention when you run over your time limit.
Practice. At least once. That way you know how long it will take.
Short, sweet and to the point. We live in an ADD world.
If it is supposed to be a case study, present a case study, not a pitch or commercial. If you can't breakdown the sale for a case study - Who, What, Where, When, Why - I have to assume that you have no idea how you won the deal or why they bought. That's great.
Less is always more. Less slides. Less words per slide. Less talking.
There is never a time when less is not better. Ever. If you can't say what you have to in less than the allotted time, you suck. And I say that with love, because if you had prepared and practiced, you would know that (A) your message was off; (B) you were running long; (C) you were not clear and concise.
Get on twitter. Now! It teaches you to speak in 140 characters, so that you can learn to be concise.
I'm not picking on you or saying I am perfect. I will say that I am always on time, prepared, and have 1 crystal clear thought: What does my audience want to know?
It all comes back to Rule # 1: Respect the Audience. And frankly most speakers/presenters/panelists don't.