5 Main Points
Once you have selected your five main points (or less), consider writing them down in a table form, as shown below.
Notice how all the five reasons are focused on the benefit to him, because I am trying to persuade him, and to sell the idea. I have my own reasons, of course, which include not wanting to have to struggle with waking him up every morning. But since this is salesmanship, he's not going to care about my reasons.
A word on audience analysis: In order to construct an effective argument, you must understand your audience. For example, the Board of County Supervisors may feel very badly that your favorite campground is about to be made into 300 tract homes, but if your protest is 10 minutes of a purely emotional appeal, you are likely to lose a very good opportunity.
Understand who you are talking to, what motivates them, and what it is within their power to do. Analyze arguments that have succeeded in the past with your audience, and figure out which key points will mean the most to them in this situation.
Organizing these five reasons next to each other instead of as a list helps visualize them along the same line. This technique helps prevent very visual people from associating a rank with these ideas--we aren't quite ready to prioritize them just yet.
When you look at the list, you may notice that some of the ideas are pretty much the same, and you can lump some concepts under others, which helps pare down the list of central ideas even further.
So now, all I have to remember are three basic points. When I'm finished having this conversation with my son, he only has three major things to recall.