Decorate the interior of your home in the same or similar style as the outside. For example, a split-level home in the mountains made of rustic-looking logs should have natural-looking furniture instead of sleek chrome and glass contemporary furniture. Use a similar style on both levels; using the same style throughout your split-level home will create a natural flow to your home so each room or space feels consistent and related to the next.
Play with different colors on each level if you enjoy a variety of colors -- as long as the colors flow and complement each other. Utilize a neutral color, such as tan, cream, white, beige or a soft gray, for the entryway and open areas, if the levels are decorated in completely different colors, such as tropical colors on the main level and dark, moody colors below. Lighter colors -- or colors that create a feeling of depth, such as sky or ocean blue -- can make the ceiling appear further away, which might be more of an advantage on the lower level where the ceiling is lower. Rich, dark colors can make rooms with vaulted ceilings feel more cozy, while lighter colors add to the open and airy feel of high ceilings.
Choose furniture that fits the scale of the room -- keeping the ceiling height in mind -- for both levels. The lower level might benefit more from streamlined pieces that aren't too tall or bulky to complement the lower ceilings, while the upper level would better accommodate taller and bulkier pieces. The same piece of furniture will look drastically different on the lower level than on the top level with vaulted ceilings.
Small details can add value to the function, style and look of your split-level home. Hanging pendant lights or chandeliers can make the upper level rooms more practical without losing the appeal of the expanse of the vaulted ceilings, whereas lamps or in-ceiling lighting will work better on the lower level. Artwork or pictures also provide a way of making the walls appear longer or shorter. Large, expansive pieces or arrangements should be put in open areas to avoid dwarfing the room. Tall, thin pieces can be placed in rooms with lower ceilings to make the ceiling appear higher. Vertical stripes or patterns are another way to visually raise the ceiling on the lower level.