Three bulbs can usually do the same job as four if they are positioned accurately. Use light from windows. Natural light is more efficient than electric, not to mention free. When you're not frolicking about in your pajamas, leave the curtains open. Paint and decorate in light colors.
Dark colors absorb light.
Light colors reflect light. The lighter the colors you use, the less artificial lighting is required to illuminate the area. Use timers when on vacation. Not only will it save energy when lights are on timers, but burglars and prowlers will have no idea that you're in Hawaii basking in the sun. Set your timer to turn lights on and off at different times on different days.