Users have been facing a battery problem on their iPhones a lot after this iOS upgrade but actually this is due to a new option which has been added in the Settings section of new iOS7 and is you have discovered it by now then I suppose battery issue must have been taken care of.
Usually till the last version of iOS we never had any control over the applications usage which are operating in the background (when you have exited them by pressing the home button) but now you have this control and believe me these background operations are the major reasons of your battery getting drained quickly.
Just follow these steps and you will be able to turn off the whole background operations for all the applications or you may do it for the specific applications. Go to the Settings section and then press general. Now scroll down a little to see the option named ‘Background App Refresh’. Tap it.
You can see the control to toggle the feature as a whole or for certain applications. My suggestion will be to target those applications who usually use the location services in background as this is the main reason to drain off your battery at a quicker rate. Toggle the options as preferred by you.
Check the Home screen of your iPhone and look out for the icon of the clock application. Take some time and look it closely, you will see that the icon shows you the real time as the date shown by the icon of the calendar application. This is something new and has not been captured by many users till now. Please let us know if you face any problem while following the tips.