Explain the disadvantages of having a messy desk. Kids often need a reason as to why they should do something before they feel motivated to do it. For example, you can tell the students that if they have messy desks, they will not be able to find what they are looking for, their papers will be bent and torn, they may lose their assignments by just stuffing them in the desk.
Explain the advantages of having a neat desk. The good attributes of having a clean desk can be used as goals for the kids to achieve. For example, the students that if they have a neat desk, they will know where all of their papers, books, and supplies are located, their papers will not be bent or torn, and that organizing the desk once will encourage them to maintain it each time they put something else in the desk.
Set aside a period of time at the beginning or the middle of the day for the students to organize their desks. By making a special time for this activity, you can get all of the students to participate. If the kids see that everyone is doing the same thing, they may find it more enjoyable.
Provide ideas about how the students can organize their materials. For example, tell the students to put their pencils in a pencil case. Tell the students that they can use one folder for classwork assignments and another folder for homework assignments. Such a system will help the students to always take home the right folder.
Set goals and provide motivation. Kids like to have something to work toward. For example, tell the students that if they keep their desks clean for a weak, then you will do an activity with them.