Build a three-minute speech around one idea
A short talk works best when every section has a purpose.
Choose a realistic budget
Three minutes at 110, 130 and 150 WPM gives 330, 390 and 450 words respectively. Reserving 15 seconds at 130 WPM lowers the budget to 357 words. These numbers describe your chosen assumptions, not a required speaking speed.
Use one example
Spend about 20 seconds introducing the question, 100 seconds on a useful example, 40 seconds on the takeaway and 20 seconds for pauses and flexibility. If you need three separate stories to explain your idea, narrow the idea.
Cut the introduction last
A clear opening helps the audience orient themselves. Before removing it, look for repeated phrases and background that does not change the conclusion. Practice with a timer instead of judging duration from the page length.