If a 'Scary' moment is planned for a scene, the scene will have to be filled with elements to emphasis the mood, for example, 'skeletons', old hunted house, blowing wind, lit candles, broken window, gray sky, full moon, old tree with no leafs, moving shadows, everything that could indicate 'Scary' mood. No one will want to add an happy items to the scene that wouldn't make the point of the story, such as presents, cakes, flowers and so on.
Stating an action must ensure that only one action is seen on the scene; It must not be overlapped with a different staged action. The drawings of each staged scene must show the idea in the simplest but most powerful way before going to the next action. You don't want to make drawings that doesn't fit or just look nice.