I’ve organized our playroom more times than any other space, and it still seems to be a complete mess on most days.
If you don't have space in the room, you can make room on the wall. You can hang your books or anything small on the wall.
If you run out of storage, you can have a storage hanger on the wall.
Instead of cramming everything in the shelf, you can use bins to keep everything organize.
If your furniture has a place for storage where you can put storage bins, take that to your advantage.