Toys are the first and foremost things. Besides, there are certain garments that may be required for frequent changing. Shelves would help you to manage these items and keep them back without much hassle. They can hold all the toys and other items required daily. These shelves should be placed at a height that is not reachable to children.
You can even plan for built-in closets behind doors if space is the main constraint. Simple boxes that can be slid under beds can hold a lot of stuff which a child may need daily. Besides, these boxes can be picked up and put away when not required. These boxes can be labeled to indicate what is stored in them.
If you are really falling short of space, you can choose small closets to store stuff and place these beside windows. These automatically can be used as window seats where kids can sit and do some activity like reading a book.
After all, every child would love to have a safe retreat for rest and play. With these storage ideas, you can keep the room clutter-free and manageable at all times.