Think back to when you were a kid, and your parents said
"Get in there and clean your room!". Chances are, by the time they got around to telling you to clean your room, they were already frustrated and your room was a disaster. You were suddenly under a lot of pressure and probably didn't even know where to start.
I love working with kids and teaching them how to keep their rooms tidy and organized. Kids don't have all the preconceived notions that adults do, so it's easier in some ways to get them to learn new ways of dealing with their belongings. I get to play fun organizing games with kids, and I get to be that third party that reinforces what you've been saying all along, but from a neutral standpoint.
The other side of that coin is that what is obvious to you and I, may not be obvious to kids because they don't have the foundation of experience that we do. So I talk a lot when I work with kids. I talk them through very basic organizing principles until I'm sure they get it. Kids also tire and get bored faster, so the sessions tend to be shorter (2+ hours, generally).
After I help my young clients sort, purge, and assign spaces for their stuff, I tell them that I'm going to show them tricks on how to make their room look tidy for mom and dad without spending a single second more than they have to. This leaves them with a sense of control, and makes way for the fun chore game of beating their own record.