Cover the outside of the bottom portion of a shoe box with construction paper in the color of your choice. Cut a piece of construction paper to fit each side of the box and glue in place with white glue thinned with water.
Paint the inside of the box with poster paints. The bottom should be brown, with green at the back of the bottom and about two thirds of the way up sides. The green should have a wavy top line, indicating hills or mountains. The top of the box and the top third of the back should be blue, to represent the sky. Allow each color to dry before applying the next. Apply white paint to the blue and green, once dry, to indicate clouds and snow on the mountains.
Cut two pine tree shapes from card stock for each tree you want in your diorama. Cut a slit in one tree shape from the top to the center and a slit from the bottom to the center in the second tree shape. Slot the two slits together, making a three dimensional tree. Paint each tree with green poster paint. Allow to dry. Pull cotton balls apart, so the cotton resembles thin snow. Glue the snow onto the trees with white glue. Set the trees around the diorama.
Set a small, frameless, round mirror on the floor of the diorama. This represents a frozen lake. Glue pulled cotton around the mirror, making snow.
Find photographs of forest animals, such as deer, elk, rabbits and bears in magazines. Cut out these pictures and glue them to pieces of thin cardboard, such as a cereal box. Cut around the picture, so it is now stiffened with cardboard. Cut a 3 inch length of thin cardboard, about 1/4 inch wide. Fold this length in half so it forms an angle with 1 1/2 inch sides. Cut a 1/4 inch slit near the edge on the bottom of the animal picture. Insert the sides of the angle into the slits, forming a stand. Stand the animals in the diorama.
Cut a circle from pale yellow construction paper. Draw craters on both sides of the circle to make it resemble the full moon. Staple one end of a 4 inch piece of string to the back of the moon. Staple the other end to the top of the diorama to hang the moon in the sky.