The most high consumption part in any Android phone, is the display. To save some battery you can easily adjust the display brightness and screen timeout
Go to Settings > Screen
Tap on the Screen Timeout
Set the new screen timeout
This option makes the display turn off after a specific time interval, when you don't use the phone or tablet.
You can also tap on the Brightness option and adjust the brightness or setting it on Auto
Note that Samsung Galaxy owners can follow the instruction easily, but the name of menus and pages on other Android devices, may vary a little .