Remove clutter from the hallway. Take down all of the wall hangings and window treatments and remove furniture, decorative accessories and plants, creating an open area to work with.
Cover the hallway walls with a fresh coat of paint. Light-colored paints -- whites, creams, beiges -- brighten an area, making it appear more open and spacious. Visually raise a low ceiling by painting it white. Satin and semigloss paint finishes have a shiny, reflective surface, enabling light to bounce off the walls and ceiling, creating the illusion of a larger space.
Frost or tint hallway windows to provide privacy, while allowing natural light to stream through the windows, creating a more open feel.
Install a skylight in the ceiling to brighten the walkway with natural sunlight by day and moonlight at night. A skylight can save energy costs, while providing continual illumination.
Position recessed lighting on a low ceiling to save space, while providing abundant illumination. Track or pendant lighting is ideal for illuminating higher ceilings, keeping the hallway ambiance open and bright.
Hang a large mirror on a wall opposite a hallway window, creating a reflective "second" window, providing the feel of a more spacious area. If the hallway doesn't have any windows, hang a large mirror at the end of the hallway, avoiding an abrupt end to the passageway.
Hang one or two pieces of framed or canvas artwork along one hallway wall to add color and visual interest, keeping the hallway ambiance open and airy. Keep the size of the art pieces in proportion to the size of the hallway. Avoid hanging groupings of pictures that can make the walkway feel cluttered.
Place a hallway runner over a wood floor to add warmth and texture to the walkway, while keeping the space free of clutter.