Install a chair rail at waist-height along the wall all around the room. This bisects the room horizontally. Paint the top half with a lighter color than the bottom half to make the room look taller. A darker paint on the top half of the wall creates a cozier feel to the space.
For homes with a great room that serves as both the dining and living room, use paint to delineate the boundaries of each section of the room. For instance, paint the dining room area one color and the living room another color. To hide the paint line, place a tall silk plant or indoor tree on the wall where the two colors meet. A faux half column, or other flat trim, installed on top of the paint junction hides the paint border with a more permanent solution.
Look at the room and use the natural architectural elements to divide the paint colors. For instance, if you have an alcove or a nook, paint the walls inside that space a different color from the rest of the room. The difference between an alcove and creating your own separate seating area with paint is the added third dimension the alcove has. It is physically set apart from the main room. Use a lighter color of paint for the walls of the alcove to brighten it and make it seem larger, or paint it with darker colors for a more intimate feel. End the alcove paint color at the corner of the wall where it meets the main room. To add a border, you might decorate the paint border with a piece of wood trim from the floor to the ceiling or create a painted stencil border incorporating the paint colors from both the walls of the main room and the alcove.
Corners of a room are used as the boundaries for different paint colors in rooms with an accent wall. The accent wall is a wall with a contrasting color used to bring attention to a piece of furniture or part of the room. In a bedroom, the accent wall would be behind the bed, and in a living room, it would be behind a fireplace or around a picture window with an especially memorable view. The accent wall color ends at the corners of the wall, where the base room color takes over. Ending a color at the corner makes a neat border. Install a strip of thin molding along the wall corner if you want to hide the color junction.