First, it’s a good idea to change a few basic settings. Because the display is one of the biggest power guzzlers on your smartphone. Not only the brightness is decisive, the time that the screen is active also influences the energy consumption.
It is therefore best to use the so-called automatic screen lock to reduce how long the display should remain on during inactivity. This means that if you don’t use your mobile phone for a longer period of time, the phone automatically goes into standby mode.
In your settings you can define after how many seconds or minutes the screen timeout activates. If the value is low, you save energy.