In working with several clients on creating and structuring their presentations, there seems to be a common theme among their efforts. They all have too much content for the time they're allotted.
Whether your presentation is ten minutes or two hours long, you will always have to edit, cut, and edit some more. We all have way more information in our heads about our topics than our audiences need or want.
In addition, if you're like a lot of us giving presentations, you don't want to give everything away in one go because you're also hoping to sell books or products or get hired for your expertise. You want to tease them a little with great content and make them want more.
Almost a year ago to the day, I wrote about time vs. information, structuring your presentation to take maximum advantage of the amount of time you have while giving the most value to your audience. If you haven't read it, I recommend checking it out now.
You don't have to share everything you know. Pick the most critical and valuable main points that your audience would want and need, and stick with those. Make sure that you're still using stories, good visuals, and audience interaction to make your content more engaging and "sticky."
Flesh out your material with some good handouts, but again, there's no need to overwhelm the audience. If they want more information, they know where to find you (that is, if you put your contact information on your handouts!).
Hold back a little. Focus on what the audience needs rather than showing how much you know. Your presentation will be lighter, less dense and more accessible.