Remove the top from a shoe box and set it aside.
Paint the inside of the shoe box a solid color. If you are making a diorama of New York City during the day, paint the box blue to resemble the sky. If your diorama shows New York in the evening, paint the box black for the night sky. Allow the paint to dry.
Cut out rectangles of various sizes to depict buildings. Use thick paper for this portion. If you are going for a realistic diorama, refer to picture of the New York City skyline
Paint the buildings black or silver and add details like windows or doors.
Glue the buildings to the back of the box.
Cut out additional rectangles of varying sizes from cardboard. Before you reach the base of each rectangle, cut small triangles on both sides. These will be folded back and serve as support for the buildings.
Paint the cardboard buildings black or silver and add details like windows and doors.
Glue the cardboard buildings to the base of the box in the middle and front of the box. Make sure the wings are folded back to keep the buildings standing. Allow the glue to dry.
Attach small trees, cars or people to the base of the shoe box with glue, if you desire.