Divide the closet in half using different styles of hangers to hang up each child's clothing on her side of the closet.
Attach wall decal stickers displaying each child's name on the wall on her half of the closet. Many closets have some wall space above the wooden hanger rods.
Place a dresser or closet organizer on each side of the closet, if the space is large enough. You can make each dresser stand out by tying different colored ribbons around the knobs to help remind the kids to keep their clothing on their side. Use the children's favorite colors. For example, use pink ribbons on one dresser for the child who loves pink, and blue ribbons on the other dresser if the child loves blue. The closet organizers can also be made distinct by tying the different colors of ribbon on them.
Fold all clothing items and put these away in the dressers or closet organizers, or hang them up on the distinct hangers, making sure to put each child's clothing away on the correct side.
Hang up a shoe organizer on the front and back of the closet door. Designate one of the organizers for one child and give the other organizer to the other child sharing the room.