Organize your grassland project by first drawing it on an 8.5-inch by 11-inch sheet of paper. Decide where you want to place plants, animals, insects and land masses common to grasslands. Taking the time to plan now will make arranging the items on your diorama much easier.
Transfer the plan you sketched on paper to your plywood. Draw lightly on the plywood so the marks or writing doesn't show through when your project is finished.
Paint each section of plywood the appropriate base color. For grasslands, you may use yellow-green, brown or brown-red paint. Use a different color to differentiate the wetland areas. Continue until your board looks the way you want it to.
Begin making the land features in a separate location. Make the rolling hills of grasslands out of papier mache or salt dough. See resources for the recipe link. Let dry. Attach the land features to the plywood with glue. Paint.
Paint rivers and other water features in the areas you have sketched out on your board. Vary the width of the rivers and the size of the lakes; in real life not all rivers and lakes are the same size.
Glue plastic bison, deer and other animals and insects onto the board. If you don't want to use plastic animals, you could make them out of clay or salt dough. Include a variety of animal and insect life as they occur in the grassland. For example, make five or six bison instead of just one because bison are herd animals. Snakes, on the other hand, are solitary, so you would need to make only one or two of each type and scatter them around the diorama.
Print pictures of the plant life common to grasslands. Cut them out and glue them on construction paper or cardstock. Make a flap at the bottom of the picture, and turn it towards the back of the image. This will stabilize the picture and make it stay upright on your project board.
Label the items on your grassland project. Each item or group of the same items should have its own label. Add a color key and a compass rose to your board.
Make a poster that contains important facts about the grassland biome. This supplemental information will be attached to the front or next to your diorama. Include high and low average temperatures, general climate, locations where grasslands are found, common plants and animals, and other items your teacher requires.