Good advice from Carleton University's Nick Rowe:
Every time I go to the [Canadian Economics Association] meetings I get disappointed at how poorly many of the papers are presented. At the risk of offending someone, I want to give some advice on how best to present a paper (or act as discussant):
Presenters should concentrate on giving us the big picture: the motivation, key assumptions, the main results, and the intuition behind those results. Don’t try and grind through countless equations in excruciating detail; you won’t have time, and nobody cares (if anyone does care about all the equations, they can do much better by reading the paper).
Speak slowly, clearly, and avoid reading from a prepared text. Yes, you risk making the occasional mistake, but the audience will be much more engaged if you speak naturally, and look at them as you speak.
If you must use slides (no, it is not mandatory), use a maximum of about 5 pages, each with a maximum of about 5 lines.
It always takes longer to present anything than you think it will. Aim at about 10 minutes, and you will probably find that you finish after 18 minutes. And there is no law against speaking for less than your allotted time; so if you do run out of things to say, just sit down, and allow more time for audience discussion of your paper.
Discussants have a harder job, because a good discussant will often change what he says in light of the author’s presentation, so you need to think quickly. You do not (normally) need to re-describe the paper; the author should already have done that. But if you have a different, and possibly better, way of explaining the paper, you should certainly take the opportunity to do so. You do not (normally) need to evaluate the paper either. Too many discussants feel they have to say the paper is a good and interesting paper, and it just comes out sounding trite. Focus instead on where you disagree with the author, or want to emphasise something about the paper or its subject that you believe the author has overlooked. If you have some ideas about how the paper could be improved, you should tell us.
From the February 2006 CEA newsletter.