How to improve your iPhone's battery life ?

1-

Turn off AirDrop except when needed

AirDrop is now available for iPhone 5, 5s, and 5c devices running iOS 7, allowing you to share files and photos with friends and colleagues over the air when they are in close proximity. But its use can take a heavy toll on your battery, particularly when AirDrop is in "discoverable" mode.
Simply swipe up from your home screen to bring up the Control Center, then tap AirDrop. Select Off when you're not using it.

2-

Limit apps from churning up data, power in the background

You can now limit which dormant apps download data, and therefore consume power, in the background. For instance, while it may be useful for a mapping app to provide you with up-to-the-minute turn-by-turn directions on the road, you may not want other apps, such as the Stocks app, to update if you're not particularly interested in the financial market.
To change this setting, tap through to Settings > General > Background App Refresh, then deselect apps that you do not want to update in the background when they're not in use.

Disable auto app updates; manually update at your convenience

iOS 7 will now update your apps and music in the background. If you're connected to Wi-Fi networks (or the cellular network), your apps will remain up to date without bugging you. But this consumes data and power, and should be restricted for when you're free to plug in your iPhone to charge.
Tap the Settings icon, scroll down to iTunes & App Store and turn off the Updates and Apps settings. Another quick power (and data) saving tip: You can allow updates when you're on Wi-Fi only by deselecting Use Cellular Data at the same time.

Block persistent callers from contacting you

Calls significantly drain your battery meter, even if you don't pick up incoming calls. If you get the same persistent person calling, you can now block them from reaching you.
To do this, head back to Settings and scroll down to Phone. Scroll down further to Blocked and select the contacts you wish to automatically refuse access. While this feature blocks the call coming through, it doesn't prevent the caller from leaving you a voicemail.

Prevent your iPhone from 'learning' your frequent locations

Your iOS 7-powered iPhone from the get-go records where you go so it can pick out nuggets of information that may help you, particularly if you visit those places regularly. It updates the Today section in your notification center, and can give you estimated times of arrival to your destinations. While it's a handy feature, it is far from absolutely necessary, and can be turned off to save some valuable battery.
Buried deep down in the device's settings, you have to navigate to Settings > Privacy > Location Services > System Services, then switch off the Frequent Locations option. You can also delete any data already collected by tapping Clear History at the bottom of the screen.

Turn off 'parallax' motion user interface

If you slowly jiggle your iPhone in your hand, you may notice the "parallax" effect of three-dimensional icons sitting on top of your wallpaper. This effect uses internal hardware to sense the direction, speed, and motion of your movements. This, as you might expect, will drain the battery. Though flashy and visually quite cool, it's not wholly necessary if you're a power user.
To disable the "moving wallpaper" feature, head to Settings > General > Accessibility > Reduce Motion, then flick the switch in the on position.
Source : http://www.zdnet.com/how-to-improve-your-iphones-battery-life-updated-for-ios7_p7-7000014902/#photo