These are some things I have learned over the years of having a home daycare and with my own kids. There are not many children who have the initiative or the knowledge to know how to clean their own rooms.
Systems should be in place as the child(ren) are growing up so that they know exactly where the homes are for the items that are strewn everywhere. Each type of object should have a space. Books can be stored on a bookshelf or in baskets. Barbies, Vehicles, Doll Clothes, Lego etc.. should all have containers that will hold all of them and then labelled on the outside (not necessary if they are clear containers). Children rarely like to hang clothing so that might be something you need to help them with.
As for dirty clothes, there should be a separate basket in each room, although a laundry sorter in the hallway could also work. Open containers and baskets work better for children as they are more likely to use it.
The best way to organize and clean with children is for you to spend time in the space with them directing them (and decluttering at the same time). Putting some music on and taking breaks every ½ hr to stretch are good ideas and the one on one time you spend with your child(ren) is priceless.
The fewer toys and clothes the kids have the more organized you will be and the less stressed.
Need help organizing and decluttering your children’s room or just want some advice? Contact me today firstname.lastname@example.org