Use less hot water
For example shower instead of bath, and take shorter showers. Only fill the kettle as much as you need it. Wash a full load of dishes, rather than one dish at a time. Use cold water where possible for laundry washing.
Switch off equipment when not in use
Turn appliances off at the wall plug, rather than leaving them on standby as this can still draw about 20% or more of normal electricity use. (Examples are TVs, music systems, computers, phone chargers etc.) Also turn the geyser off when you go on holiday.