Use a portable solar panel charger for your phone.
Turn off the lights when you go to sleep.
Keep the television off when you are outdoors.
Use a fan instead of an air conditioner if possible.
Buy an energy-efficient air conditioner if you need one.
Don't leave the hot water tap unnecessarily open.
Don't let the water run unnecessarily while brushing your teeth.
Use a gas barbecue instead of an electric barbecue.
Use a kettle with an automatic shut-off function to prevent water from boiling unnecessarily.