Setting > wifi & Bluetooth ( turn them off if you don't use them )
Setting > Sound > Sound Level ( make less level)
Setting > Sound > Vibrate on ring ( switch off )
Setting > Sound > Vibrate on touch ( switch off )
Setting > Screen > Brightness ( make less level)
Setting > Screen > Sleep ( 15 Seconds )
Setting > Developer Options > Window animation Scale > Animation off
Setting > Developer Options > transition animation Scale > Animation off
Setting > Developer Options > Don't keep activities ( Switch on ) not Recommended
Setting > Sound > Sound Level ( make less level)
Setting > Sound > Vibrate on ring ( switch off )
Setting > Sound > Vibrate on touch ( switch off )
Setting > Screen > Brightness ( make less level)
Setting > Screen > Sleep ( 15 Seconds )
Setting > Developer Options > Window animation Scale > Animation off
Setting > Developer Options > transition animation Scale > Animation off
Setting > Developer Options > Don't keep activities ( Switch on ) not Recommended