Mute unnecessary sounds, such as touch sounds. Tap Settings > Sound > Advanced, and under Other sounds and vibrations, select which sounds to keep.
Use a wired headset, rather than the loudspeaker.
Set the phone screen to switch off after a short time. Tap Settings > Display > Sleep and select the time.
Tap Settings > Display > Brightness level. Make sure that Adaptive brightness is off. To adjust the brightness, drag the brightness level slider.
Stop apps from running in the background: tap check_box_outline_blank and close the apps you don’t need.
Switch on the power saver: Tap Settings > Battery > Battery saver and switch to On.
Switch location services off when you don't need them: tap Settings > Security & location and switch Location 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 flight mode on. Tap Settings > Network & Internet > Flight mode.
Flight mode closes connections to the mobile network and switches your device’s wireless features off.