Many conferences and workshops have been moving from the traditional presentation and poster sessions to use alternative mechanisms for disseminating information. Amongst the most popular are the short talk formats including: the lightning talk, Pecha Kucha (20x20) and Ignite.
Each of these allows many speakers to present in a session, and uses a format which introduces urgency to combat "death by powerpoint". Lightning talks are typically 5 minutes long (as opposed to the 25+5 format for a normal presentation slot), whereas Pecha Kucha (20 slides each shown for 20 seconds) and Ignite (20x15) have the additional impetus of automatically advancing slides after a fixed amount of time.
So how can you learn to give a good lightning talk? Delivery is more important than content!
It's important to remember that most of the guidelines for good presentations still apply. You should still make eye contact with the audience, you should still be prepared to stop earlier or handle awkward questions, you should still remember to go to the bathroom beforehand. What the short talk format provides you with is a framework to get down to the essence of what you are trying to say to the audience.
Make your point, Make it quickly
Think about what you are trying to get your audience to discover! If you are talking about your work, are you presenting the audience with an unsolved question? Or an inspirational answer! Make it your title, so that people have had time to digest it and get interested.
Get to your point early on. Don't leave it to the end. If you can make your point in 1 minute or 1 slide then go for it.
Don't sweat the small stuff
Lightning talks are there to enable the audience to review as many potentially exciting ideas as possible in a short space of time. You are not there to provide the detail required for them to reproduce your work, you're there to inspire them to search out your work.
Use large images and as little text as possible. Don't crowd and confuse with unnecessary information - have a pointer to a website or email at the start and/or on every slide to give your audience more. You might even like to use the Takahashi method which uses only one or two words per slide.
When structuring your slides don't worry about taking wild leaps, and when talking provide the minimum amount of background to give the context to make your point.
People want to discover something new, not everything there is to know about it.
Practice against a timer. Practice standing up. Five minutes is a really short time when presenting. And yet make sure you go slow and steady and reduce the amount you say rather than rushing to try and cram more in.
Make sure you know how the microphone and other A/V facilities work. Understand when you'll be presenting and be ready to speak.
And remember, the audience is on your side!
In summary, remember that DELIVERY is more important than CONTENT. This doesn't mean that your content shouldn't be good, but that it is always better to get across something that sticks in your audience's mind, than getting them to forget everything you've just said.
After all, you want them to come and ask you questions in the coffee break!
Some useful references: