It's true that Computer is indeed a boon to a scientist making a presentation. Yet it is important that the presenter himself is adequately prepared for a good presentation. He needs to plan carefully and follow a few basic steps.
A good scientific presentation starts from the time a paper is conceived. If you want to present a good paper, ensure that the concept is good, well thought, designed aptly, results well analysed and valid conclusions are made. You should have your ground work done and write the draft of the paper, before embarking on a presentation. A well-written draft will provide the frame work of a good presentation.
Your work starts as soon as you hear that the paper has been accepted. After acceptance, you need to plan the slides, the slide text and rehearsals to fine-tune the talk.
How many slides do you need? - It depends on your presentation. For an eight minute presentation it is ideal to have seven pairs or 11 to 12 pairs at the maximum, assuming each slide will take 30 seconds for projection and explanation.
Slides constitute the backbone of a presentation. Therefore, a lot of thinking is needed before preparing your slides. Use colours judiciously, not too many of them. Use separate colours for heading and text, as it will help in discrimination.
Use computer graphics for slides with a dark colour for background, light colour for the text. The standard background is dark blue and the standard text is yellow or white. Do not use red letters on blue or green background. It will simply not be visible.
When you design a slide, project important points, use telegraphic language. Sentences should not be too long. Seven double spaced lines are maximum. Three to four lines in the text will be appropriate.
In the slides, graphs and tables have to be well represented. Remember a detailed graph which you will be presenting in a paper may not be good in your presentation. You can simplify it to maximum of 3 columns, five rows.
In the presentation, photographs can be one of the major strength. Quality of the photographs needs to be of high class. Select photos very carefully. You can show a representation of your results by a photograph. You may improve the quality of your photograph by editing it.
For the presentation, always prepare a spoken version. Even if you think you are an experienced presenter, write what and how you will be speaking to your audience. Do not speak what is written in the book. It will be dull and boring. Use small sentences to emphasize certain points. Do not use emotional words and superlatives. Use preferably scientific expressions. Do not use sentences like "We got fantastic results following foldable intraocular lens implantation" or "For the first time anywhere in the work—"
Once you prepare your spoken version, note the timing, plan to finish 45 seconds or one minute before, during the rehearsal. You can really undo all your good work just by not being careful about your time. Once you start preparing, you will always have a tendency to add. Be ruthless and avoid that. Our one important goal is to finish in time.
It is extremely important and advantageous that you rehearse your presentation. I do not think you can manage it "just like that" on stage. According to Murphy's Law, "anything that can go wrong will go wrong". It is best to present before peers, colleagues. Make slides for final presentation a week ahead. After the slides are made, rehearse two to three times at least. Once you are set, stop this and do not overdo.
In the slide presentation, it is important that you do not read word by word because the audience reads faster; you just amplify them. Try to avoid telling something which is not written in the slides. Keep the order from top to bottom. In case of graphs, tables and photos, orient them first. Take the audience with you walking through the slides. Judicious use of a pointer can make your presentation quite effective. Move the pointer slowly and precisely. Don't wave the pointer around in a circle in the vicinity of interest. On the day of your presentation, go to a preview room an hour ahead. Project the slides in the computer monitor and check whether your photos are in the right direction and slides are in the right sequence. It should go smoothly.
You should go to the podium before the session starts. See the microphone, the projector control, the pointer and the video setting. For an effective presentation, you need to be in perfect control of these arrangements and should not search for help while presenting.
While presenting stand erect, leaning too much will look bad. Do not over dress. Do not move too much, and use body language a bit but not too much. Take the microphone properly, not too close, not too away. You may have slide text written in bold letters in paper or cards which you can use as reference. Keep eye contact with your audience.
Once your presentation is over, you may have to face questions. Have a very thorough idea about your paper. A good presentation also means how you handle the questions. Review your data for likely questions and keep some general answers in your mind. One can really make a mess of a good presentation by answering improperly. Listen to the question. If you have not understood, ask the questioner to repeat it. Do not be in a hurry to reply.
Be humble, differ with politeness, agree to disagree. You will have the audience with you if you are polite and lose if you are not. Give answers like "I am afraid that it may not be true". Answers like 'we need to look into that aspect' are safe. It is much better to admit ignorance than make up some poor answers.
Last but not the least, presentation may be good but the story is not complete unless you write up your presentation as a paper and attempt to publish it in a journal. Remember, by publication you get a permanent place in the annals of medicine. Finally, always finish in time.