Here is a list of options which can be changed to increase battery life.
Check Battery usage: Settings > General > Usage > Battery Usage
1. Update iOS software. Settings > General > Software Update
2. Disable AirDrop. Swipe up from your home screen, then tap AirDrop select Off.
3. Disable Background App Refresh. Settings > General > Background App Refresh. Disable any unnecessary Apps.
4. Disable Automatic Downloads for Music, Apps and Books. Settings > iTunes & App Store
5. Disable Location Services. Settings > Privacy > Location Services Disable items or turn off completely.
6. Disable auto-brightness and adjust manually. Settings > Display & Brightness
7. Disable diagnostic data to Apple. Settings > Privacy > Diagnostics & Usage and select Don’t Send.
8. Disable Parallax. Settings > General > Accessibility > Reduce Motion
9. Turn on WiFi when available.
10. Turn off Bluetooth when not in use.
11. Set auto-lock to lower setting. Settings > General > Auto-Lock, set to 1 minute.
12. Close Apps after use. Double-press the Home Button or Swipe up halfway on your screen, holding your finger on the screen and swipe up to close Apps.