I learned these lessons on how to do a presentation. The key points one has to address while preparing a talk are
- Who will be my audience? This is what should guide in the design and layout of the talk. It decides over what degree of detail to present, ranging from raw data and formulas to graphs of the basic relationships over to cartoon representations of the physical problem.
- How many messages does one slide carry? It should not be more than two. Usually, things are complicated. It is preferred to broadcast fewer information, but have that information understood instead of broadcasting masses and nothing is understood: "If they understand a little, that's better than if they didn't understand a lot." If one slide refers back to a previous one, include it on the slide in a small version to help keeping it in memory. It is also a good idea to keep a couple of extra slides which contain more details, just in case.
These are the lessons I learned up to now on how to present a topic at a talk.