I hate to break it to you, but just as with losing weight or quitting smoking, you will never succeed in motivating someone else to get organized. People only change when there is some internal, personal goal driving them. Organizing is too tough a journey to take just to please someone else (no matter how much they care about you). Nagging doesn’t help. In fact, the more you yell, lecture, threaten, tempt, cajole, and beg, the more closed off, defensive, and resistant to change the person is likely to become.
It seems counterintuitive, but by taking yourself out and your own frustrations out of the picture, you are in a much stronger position to facilitate change.
The secret to breakthrough is to tap into the person’s own motivation, which you can usually do by asking one simple question: What is the clutter costing them.