Starting with age 5, have a family rule that your child makes their bed every day--and then don't fix their work. This post has 100+ ideas to help you tame the chaos in your home (and your life). I like the lost sock hanger.
We did this in our main level bathroom, using Velcro tabs. I also bought 2 18qt dishpans at Dollar General to keep the "inside" orderly. *Note: Careful applying pressure to door. Ours broke off - wood glue to the rescue. Love DIY projects!