One should use power saving mode that is now available on almost all smartphones.
Stop the notification of unwanted apps.
Use auto-brightness mode to reduce consumption of the battery
Use only still wallpapers instead of animated ones.
Keep the phone in moderate temperature for long-lasting battery backup.
Close the apps that are running in the background for less battery consumption.
Turn off location service when you do not need it to save battery life.
Using the phone in dark mode is the best way to extend its battery life.