According to the US Dept of Energy

The quantity and quality of light around us determine how well we see, work, and play. Light affects our health, safety, morale, comfort, and productivity. In your home, you can save energy while still maintaining good light quantity and quality.
Consider using high-intensity discharge (also called HID) or low-pressure sodium lights.
Exterior lighting is one of the best places to use CFLs because of their long life. If you live in a cold climate, be sure to buy a lamp with a cold weather ballast since standard CFLs may not work well below 40°F.
Turn off decorative outdoor natural gas lamps; just eight such lamps burning year-round use as much natural gas as it takes to heat an average-size home during an entire winter.
Use outdoor lights with a photocell unit or a motion sensor so they will turn on only at night or when someone is present. A combined photocell and motion sensor will increase your energy savings even more.
Consider using 4-watt minifluorescent or electro-luminescent night lights. Both lights are much more efficient than their incandescent counterparts. The luminescent lights are cool to the touch.
If you have torchiere fixtures with halogen lamps, consider replacing them with compact fluorescent torchieres. Compact fluorescent torchieres use 60% to 80% less energy, can produce more light (lumens), and do not get as hot as the halogen torchieres. Halogen torchieres are a fire risk because of the high temperature of the halogen bulb.
Take advantage of daylight by using light-colored, loose-weave curtains on your windows to allow daylight to penetrate the room while preserving privacy. Also, decorate with lighter colors that reflect daylight.
Recessed downlights (also called recessed cans) are now available that are rated for contact with insulation (IC rated), are designed specifically for pin-based CFLs, and can be used in retrofits or new construction.
Use CFLs in all the portable table and floor lamps in your home. Consider carefully the size and fit of these systems when you select them. Some home fixtures may not accommodate some of the larger CFLs.
Consider using 4-watt minifluorescent or electro-luminescent night lights. Both lights are much more efficient than their incandescent counterparts. The luminescent lights are cool to the touch.
Use 4-foot fluorescent fixtures with reflective backing and electronic ballasts for your workroom, garage, and laundry areas.
Consider three-way lamps; they make it easier to keep lighting levels low when brighter light is not necessary.
Use task lighting; instead of brightly lighting an entire room, focus the light where you need it. For example, use fluorescent under-cabinet lighting for kitchen sinks and countertops under cabinets.
Turn off the lights in any room you're not using, or consider installing timers, photo cells, or occupancy sensors to reduce the amount of time your lights are on.
Install task lighting – such as under-counter kitchen lights or bathroom mirror lights – to reduce the need for ambient lighting of large spaces.
Use dimmers, motion sensors, or occupancy sensors to automatically turn on or off lighting as needed and prevent energy waste.
Install fluorescent light fixtures for all ceiling- and wall-mounted fixtures that will be on for more than 2 hours each day.
Use ENERGY STAR labeled lighting fixtures.
Consider light wall colors to minimize the need for artificial lighting.
Use compact fluorescent light bulbs (CFLs) in place of comparable incandescent bulbs to save about 50 percent on your lighting costs. CFLs use only one-fourth the energy and last up to 10 times longer.
Turn your lights off when you leave a room. Standard, incandescent light bulbs should be turned off whenever they are not needed. Fluorescent lights should be turned off whenever you'll be away for 15 minutes or more.
During winter, open curtains on your south-facing windows during the day to allow sunlight to naturally heat your home, and close them at night to reduce the chill you may feel from cold windows
Installing a skylight can provide your home with daylighting and warmth. When properly selected and installed, an energy-efficient skylight can help minimize your heating, cooling, and lighting costs.

Lighting

• Turn off lights when not in use.
   
• Use task lighting whenever possible instead of brightly lighting an entire room.
• Install compact fluorescent lamps in the fixtures which receive high use.