Mute unnecessary sounds, such as touch sounds. Tap Settings > Sound > Advanced, and under Other sounds and vibrations, select which sounds to keep.
Use wired headphones, rather than the loudspeaker.
Set the phone screen to switch off after a short time. Tap Settings > Display > Advanced > Sleep and select the time.
Tap Settings > Display > Brightness level. To adjust the brightness, drag the brightness level slider. Make sure that Adaptive brightness is disabled.
Stop apps from running in the background: tap check_box_outline_blank, and close the apps you don’t need.
Enable the Background activity manager. The notifications of some apps or emails may not be able to be retrieved instantly. You can manage the battery life by adding or removing the apps to or from the whitelist. Tap Settings > Battery > Background activity manager.
Switch on the power saver: tap Settings > Battery > Battery saver, and switch to On.
Use location services selectively: switch location services off when you don’t need them. Tap Settings > Security & Location > Location, and switch to Off.
Use network connections selectively:
switch Bluetooth on only when needed.
Use a Wi-Fi connection to connect to the internet, rather than a mobile data connection.
Stop your phone scanning for available wireless networks. Tap Settings > Network & Internet > Wi-Fi, and switch to Off.
If you're listening to music or otherwise using your phone, but don't want to make or receive calls, switch the airplane mode on. Tap Settings > Network & Internet > Airplane mode.
Airplane mode closes connections to the mobile network and switches your device’s wireless features off.