I'm always careful about my phones battery usage so I'd like to share some tips on how to conserve battery.
1. Switch your preferred network type to 2G when not using mobile data. 2G signal has much better building penetration than 3G and LTE signals, so your phone will spend less time hunting down a weak signal.
2. If you don't use Google Now, you can try turning off Location Reporting to stop your phone from constantly waking up and sending GPS coordinates to Google.
3.Under WIFI > Advanced, turn off WIFI Scanning Always Available, so that your phone doesn't constantly try to search for access points even when your WIFI is turned off.
4. Disable applications you don't use so they don't run in the background and also to free up some internal storage space. Be careful not to disable system services as they are critical to the operation of the device.
5. If you have any apps that automatically backs up your data, there may be an option to do so only when you're charging your device and if it's connected to a WIFI network. This will help conserve data usage and battery usage when your out and about.