Spread a butterfly or moth using a spreading board. Write labels neatly and tiny. Follow the examples. Learn some special collecting techniques. Collect under lights at night.
Black lights are best.
Place out pitfall traps. Use a little soap in water or just bait. Sugar baits can be used in traps or painted on trees at night. Use a flash light on your forehead to find spiders at night. Use the materials in the insect study merit badge to identify insects.