Set the screen brightness to low. Note: To access, from the Settings screen, go to Display > Brightness> Adjust the brightness.
Set the screen timeout to a shorter duration. Note: To access, from the Settings screen, go to Display > Backlight duration > adjust the timeout length.
Turn Bluetooth off when not in use. Note: To access, from the Settings screen, go to Connections > Bluetooth > Bluetooth.
If you are traveling and do not have access to mobile or Wi-Fi networks, switch to Airplane mode. Note: From the home screen press the Left Soft key > scroll to, then select Settings > scroll to then select Airplane mode > scroll to then select On to enable.