Every NFL team methodically practices their two-minute drill: a strategic sequence of plays designed to move the ball into scoring position in a highly-condensed timeframe.
I often use a similar approach in my work. When helping clients preparing for their presentations – which are typically 15-30 minutes in length – I ask them to practice a two-minute version. I make this suggestion late in the process, once the main presentation is in good shape.
Here’s why: the shortened timeframe forces us to refocus on what's most important about our story. Once we've clearly prioritized our content, we're in a better position to land those key points in a presentation of any length. 
As you prepare to give a talk, I suggest you practice your two-minute drill. It will help you perform better when it's game time. 
You’ll also be better prepared to handle the unexpected, as happened to a client in May, when he was asked on the spot to deliver his 20-minute talk in less than 5 minutes. He was ready!