Let's get one thing out of the way. This method has nothing to do with stringing wall-to-wall slides together and using them to prompt you. I'm going to assume that the screen is blank unless your words need specific visual support. In other words: this will be about how to organize your thoughts swiftly for an effective presentation.

Here's the essence:

1. Write a purpose statement.
2. Write your key messages as the subheadings (what must be said).
3. List supporting detail under each key message - in order of importance.

Follow me through this simplified, fictional example. 

You're an IT Manager. You're about to present to the board, to recommend what your research reveals as the best replacement for the computer hardware and network system.  The existing system is obsolete. It's low spec, it's slow, it can't handle modern demands, particularly security. In one year, outage frequency has doubled, maintence costs have tripled. Your proposed new system would have cutting edge specs, including world standard security. It would be designed and installed by Compak Solutions, which has a reputation for reliability. Although the cost is high - $7 million - it will pay for itself within 3 years. Compak will guarantee maintenance and future-proofing for the next 4 years.

1.  Write a purpose statement (first words after the greeting)

I want to recommend a replacement for our obsolete computer system.

Note that it's not a 'talk-about' title (e.g. 'I want to talk about the computer system'). Instead, it's why you're really there, your real purpose, what you really want to achieve with the audience: make a recommendation.

2.  Write your key messages as the subheadings

What must be said. Here are three likely ones you might choose:

We're at crisis point now  / The new system will fit our needs / It would pay for itself in 3 years

Note how dynamic those subheadings are.  How different from the usual way with neutral subheadings (which, in this example, might have been Background / Proposed system / What's ahead, or the standard What / Why / How structure. 

3.  List supporting detail under each - in order of importance

There's a bonus to listing in order of importance. If you turn up with your 30 minute presentation and the chair tells you you've now only got 3 minutes, it's very easy to drop the bottom points in each list. You will still have a dynamic, effective presentation.

Any worries about identifying the key messages? Here's a tip. Imagine that your audience is standing up and about to walk and you have to blurt out what they really must know in a just a few short words. Chances are you'll get your key messages right there.

Have fun. Organise to grab and hold their attention.