Brainstorm with the child about the scene in which they would like to place their Snoopy doll.
Have the child draw and color on sheets of construction paper to create a background, ceiling or "sky," and a ground pattern for the diorama's scene.
Cut down the construction paper to fit into the back, top and bottom of the shoe or cardboard box.
Glue the background to the back of the box (what would ordinarily be the bottom of the box, when used as a shoebox or to contain items).
Glue the top and bottom pieces in place.
Allow the child to further decorate the backgrounds with more color, poster paint or glitter, as desired.
Have the child create additional decorations using yarn, clay or other materials. For instance, they can create a table or a bed for their Snoopy figurine if the scene is indoors, trees and flowers for an outdoor scene or rockets and planets for a space scene.
Glue decorations in place.
Place Snoopy in his diorama environment.