First, turn off unnecessary location services.
Select Privacy in the settings, and then select Location Services to turn off location services without uncommon applications.
Second, turn off the background app refresh.
Go back to Settings and select General, then find the background app to refresh and open, and then close.
Third, turn off the app update.
Go back to the settings and select the activation button of App Store to turn off automatic updates.
Fourth, weaken the dynamic effect.
Go back to the setting and select the auxiliary function, select the dynamic effect, and turn on the weakening dynamic effect.
This is how Apple 12 saves electricity. I hope it helps you.