1. This is a RULE: NEVER GO OVERTIME. If you are giving a "one-hour" seminar, then stop after 50 minutes to leave time for questions. Anticipate interruptions during the talk and plan for those. This rule holds even if they do not start the seminar on time (they rarely do).
2. End the talk definitively, e.g., say "Thank you," not "That is all I have to say."
3. Your slides must be readable to the entire audience. Also – too much on one slide scares the audience, even if they can read it.
4. Give a strong, conceptually oriented introduction. Be as brief as possible while still making all of your points. Be sharp at the beginning. Remember the 20 Minute Rule: You should show a data slide no more than 20 minutes into your talk (or your audience has the right to get up and walk out!).
5. Briefly outline the talk somewhere near the beginning – people like to know what to expect.
6. Methods: Mention them briefly when necessary to explain the experimental results. This should be a miniscule part of most talks. Never go on and on about how hard the work was. Do not belabor your statistics.
7. Sample sizes: If you have significant differences then you don’t usually need to include them. They can be included if they do not clutter the slide.
8. Never apologize for anything.
9. If you’re not going to talk about something, then don’t bring it up only to say that you’re not going to talk about it.
10. Conclusion slide: above all make it brief. Better yet, have a take-home message slide, and don’t treat the talk as a mystery novel.
11. Don’t say, “I put this in to remind me about …"; it reminded you, so keep going.
12. Organize things so that you don’t have to repeat things too often.
13. Humor is best used to make the audience remember something about the science.
14. Remember – people can read.
15. Be yourself: if you are intense, be intense. If you are relaxed, be relaxed. If you are funny, be careful.
16. If you have a "thank you" slide, keep the time you focus on it to an absolute minimum.
17. Don’t be afraid of finishing early. No one will hold this against you. Trust me. The worst seminars are those that try to take up 50 minutes to talk about something that can be discussed in 20 minutes.
Lynda F. Delph is professor of biology at Indiana University at Bloomington.