Research shows that the average audience member can hold and retain about 3 to 5 ideas in his working memory and his attention span lasts an average of 25 minutes. What this means is that if you bombard your listeners with a topic like a "15-point Action Plan to Diversifying Your Income", they'll probably end up remembering less than five points and the rest will be quickly forgotten, even before they walked out the door!
First, select the 3 or 4 most important points out of the 15 you have on your list and develop your presentation around these few. Second, put the rest in a well-printed handout and distribute to the audience after your presentation.
Your explanations of the main points during your talk should help them understand the remaining (less important) points when they settle down to read your handout at home or back in their offices.
However, if your presentation is such that the audience must take a decision right there and there's no chance for them to go away and read the handout, then, you could try distributing the handout BEFORE your presentation. Give them time to read it through (up to 10 minutes) before you start. This way, you get to cover all your points without overwhelming them with too much.
The positive side of this strategy is that, having read your handout and now listened to your speech, the audience will (or should) come up with a lot of questions for you after your presentation. Now, except you're one of those who fear the Q&A, you should be happy about this. The Q&A session is a personal favourite whenever I have to educate or persuade an audience on anything. Every confident speaker/presenter always looks forward to it, and so should you.
Using only a few main points in your presentation is one of several ways to make messages that stick. So, the next time you're giving a presentation, do not overwhelm your audience with too many points. Slim your content down to three or four main ideas, and focus on them.
I would rather entertain and hope that people learned something than educate people and hope they were entertained. - Walt Disney