Kids rooms can be one hot mess! One of the best tips I ever learned for helping your child stay organized in his bedroom was to take a photograph of his room after it had been cleaned up and then blow it up into a poster and frame it on the wall.
Whenever the child (this works well with younger children or children who have difficulty with organization) needed to be reminded of where things go, all he has to do is look at his poster to see where to place everything.
What an amazing idea. I don't know who came up with it, but I loved it and used it with two of my kids who were organizationally challenged.
P.S. They were the most creative kids but not keen on cleaning or organizing.