There are lots of ways you can conserve battery power in your smartphones. I will simply list some of them
1. Reduce the number of apps running in the background.
2. Reduce the display brightness and also turn off the auto-brightness mode.
3. Use static wallpapers instead of live wallpapers
4. Clear your homescreen of widgets you don't use.
5. Make sure your apps are up to date, cos outdated apps will always function below optimum level.
6. If you have a power-saving mode, use it.
7. Turn off wifi, bluetooth, nfc etc.
8. Turn off automatic notification for your email and social network feeds.