How can I effectively fill in scratches on wood surfaces?

To effectively fill in scratches on wood surfaces, you can use wood filler or a wax stick that matches the color of the wood. First, clean the scratched area and let it dry. Then, apply the filler or wax stick to the scratch, following the manufacturer's instructions. Once the filler has dried, sand it down to make it smooth with the surrounding wood. Finally, finish by applying a coat of wood polish or sealant to blend the repaired area with the rest of the surface.