First of all, let's make it very clear--you can never organize someone else. They will resist you even if they want you to organize them. I am talking about your family-- mostly your children and spouse. The best you can do is to corral them. They will thwart your every attempt to help them make it easier to walk through their room. You can buy them cute little baskets and bins and they will throw their stuff on the floor. Because that's where it belongs. So, relax and enjoy them while they are still under your feet and at home. This too shall pass. Make sure there aren't any moldy things in the closet, but save your time and pick up their stuff 10 minutes before company come.
Teenagers?? We'll talk later.