Turn off lights, fans, A/Cs, TVs, computers, battery chargers, etc. when not in use.
Turn off air conditioners or room heaters well before leaving the house.
Turn off electrical appliances instead of using standby mode.
Use dim light at bathrooms.
Use dimmer control or rheostat / variable resistance to control brightness of table lamps.
Use energy saving lamps like CFL (compact fluorescent lamp).
Paint walls of rooms white or bright.
Allow maximum sunlight during the day and turn off power supply to some lightings accordingly.
Clean air conditioner filters periodically.
Power saved is power produced.
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Several tips: Save Electricity. Save Energy. (Power Saving Tips)