First off, you don’t.
The best presentations are still those that were prepared well and rehearsed. But we don’t always have the luxury of time in the corporate world. More often than not, we are told to give presentations on the day itself. Worst case, you have ten minutes to prepare.
If suddenly you are put on the spot to prepare a presentation with a deck in 10 minutes, do not panic. Here are some things you can do.
Summarize what you have to say in 1 sentence. What is your thesis? What is it you wanted the audience to take away from your presentation. If you are asked to present numbers, what is the bottom line? If it is a project, what kind of support do you want from your audience? If it is a decision point, which choice are you leading them to? Write that sentence and put it in one slide.
Break down your story into three parts: 1) the protagonist and his problem, 2) what needs to be done to overcome this problem, 3) what will happen if the problem is overcome. If the presentation is to your bosses or clients, more often than not, they are the protagonists. In that case, parts 1 and 2 are setups to your one-sentence thesis.
Look for appropriate images that can summarize parts 1-3. The key to looking for images is summarizing your point into a word, and then looking for an image that best represents that word. Best if you used images that you already have with you or photos that are about the company and the people in it. If you do not have those, you can always google images that are royalty free.
If you do not have enough time to browse through images, putting keywords on slides should be enough. Make them large, easy to read, and few. Don’t put paragraphs. If you can avoid sentences, do so. Phrases are very good. Single words are the best.
Take time, even for a minute or two, to rehearse with your instant deck. Run through the slides with your key points. Rehearse the timing of your slides in relation to your key sentences. Sometimes, the theatricality of the synchronicity of your speech and your slides will make it dramatic enough to drive home the point.
Of course, always, storify your presentation. Begin and end with a story. Or frame the entire thing into a single story. Use a story that is yours, a story that you know very well so that your audience can feel that you know very well what you are talking about. This immediately disarms your audience and makes them more attentive.
End strong. With a question maybe? Or a strong statement? Best, with a compelling story. Most importantly, make them feel that you have prepared well for this presentation long ago and not ten minutes before you walked into that door.