You glance at the clock and gulp; then you agree to help out your colleague. You immediately clear your calendar for the afternoon. Instead of going into panic mode, you create a plan of attack.
When you’re asked to speak on short notice (or on any occasion, for that matter), there’s no such thing as too much information. The more information you’ve got, the better. In your haste to start preparing, you might overlook important details. Use the following as a starting point of a pre-speech checklist.
No need to reinvent the wheel
You’re doing them a favor by speaking at the last minute. Ask whether they can do you a favor in return. Perhaps there’s a related topic that you’re more comfortable addressing. See if there is any leeway in the subject matter. If so, tailor it toward a topic or facet of the specified subject matter about which you are more knowledgeable.
If you’re lucky, perhaps you’ve already spoken on this topic. As long as you’re addressing a new audience, repurpose your old speech.