How do I divide a room?

No doubt there are some creative ways to accomplish this. Could you share a picture of the space? That would be helpful.

If the room is big enough, you can use bookcases to divide the space. Another option is to install a curtain from the ceiling. My friend and his older brother shared a room when they were kids. His brother was a class A slob and my friend was not. Their dad painted a stripe down the center of the room. They each had their own side. Also did it in the closet. Problem solved.

You can purchase some bookcases or cubbies and back then up to each other to divide the room and add storage.

I think those IKEA Billy bookcases are good, these are deep enough to have both sides used with enough space for each boy.