Stick to colors like beige or gray, especially on the first floor, where flow is important. "You want to minimize jarring transitions," says Breining. Neutral walls give you the greatest decorating flexibility, allowing you to easily switch up your accessories. And if you have two small rooms next to each other, painting them the same neutral color helps them feel larger. Look at a paint strip and move up or down a shade or two for a subtle variation from room to room, suggests Allen-Brett.