Here's how to make your iPhone 4S battery last longer.
1. Go to Settings.
2. Go to General then Reset.
3. Choose Reset Network Settings, and your iPhone 4S will restart.
4. Now go back to Settings then go to Location Services and turn off all location services that you don't really use.
5. Now go to System Services and disable Location Based iAds and Setting Time Zone.
6. Go to General then About then Diagnostics and Usage. Tap "Don't Send" to turn off automatic sending of diagnostic and usage data to Apple.
7. Go to General then Siri and turn off "Raise to Speak."
For more, see the original article at the link below.