Turn off Background Refresh for apps you don’t care about
This keeps the phone active and doing things in the background, including polling the data network, which reduces battery life. Go to Settings > General > Background App Refresh, and either turn it off globally, or deactivate it for certain apps as you see fit. When you return to the app, it may take a moment longer to bring you new information, but it otherwise shouldn’t have any effect on how the app works.
Disable as many notifications as possible
You can leave important ones (such as text and voicemail) intact, but for most apps, you probably don’t need the phone waking up and displaying notifications all the time. Head to Settings > Notification Center, scroll down to Include and Do Not Include, tap a given category (Phone, Messages, Reminders) or app (Facebook, Twitter, etc.), and choose as few notifications as possible. The fewer you enable, the more standby time you should see. While you’re in there, note that you can change the way each one appears (Alert Style) and whether it shows on the lock screen, as well as disable it entirely.
Check for software updates
Software updates will often contain fixes that enhance battery life. You can check for OS updates right from the phone, instead of using a USB cable and syncing with iTunes. Simply head to Settings > General > Software Update.
Turn off Location Services and Frequent Locations
This is a big one, as hitting the iPhone’s GPS constantly can blaze through your battery. Head to Settings > Privacy > Location Services to cap this behavior. You can tap the On/Off slider next to Location Services to turn all of them off, but you can also disable these services on an individual app basis below. Many apps don’t need to know your whereabouts, especially in the background. Another one to be aware of is Frequent Locations, a relatively new feature that tracks where you are most often in order for apps to send you targeted ads; aside from being annoying, it also drains battery. From Location Services, scroll down to Frequent Locations and turn it off.
The old power-saving standbys still help
You can still do all the basic, old-school things to improve battery life, such as reducing screen brightness, disabling Wi-Fi and Bluetooth, and so on. The one that helps most here, in my experience, is screen brightness, but you still need to crank it up to see the Retina Display in bright sunlight.
Sources: pcmag.com; buymondo.co.za