 Update to the Latest Software:
Make sure your iPhone has the latest software , as engineers may find new ways to optimize battery performance.

 Turn down screen brightness:
When you’re in battery life saver mode, turn the brightness all the way down. It sucks more energy from your battery.

 Turn off Push Notifications and Push Mail:
If you have a Push email account set up, turning the push off temporarily will save some battery.

 Fetch new data less frequently:
Rather than having it set to “Every 15 minutes”, set it to “Manually” or “Hourly”. It will save some your battery power.

 Turn off WiFi:
Both WiFi and “seeking” new WiFi connections drain battery power. Turn them off when not in need of high speed internet.

 Turn off 3G:
If you’re really low on battery, and are willing to do whatever it takes to keep the phone alive for emergency situations, then turn off 3G.

 Minimize use of location services:
Since this requires the use of GPS, using location services sucks more energy from your battery.

 Turn off EQ:
Applying EQ settings to your iPod apparently drains extra battery. If you’re planning on keeping your phone alive all day, turn the EQ off.

 Set Auto-Lock to 1 Minute:
When you’re not using your phone, lock it.

 Use 3D Game apps less frequently:
3D Games drain the battery extremely rapidly, so use them sparingly.

 Turn Off Vibrate in Games:
A lot of games have very frequent vibrations, which drain battery life. If you can, turn them off in the game’s settings.

 Don’t use Bluetooth:
Turn it off when you are not using.

 Auto-check less email accounts:
You can save power by checking less email accounts

 Use Airplane Mode in low- or no-coverage areas:
Turning on Airplane Mode can increase battery life however, you will be unable to make or receive calls.

 Temperate maintenance:
IPhone works best from 32° to 95° F. You should store it in environments of -4° to 113° F. That’s 0° to 35° C and -20° to 45° C for the metrically inclined. Keeping your iPhone as near room temperature as possible (72° F or 22° C) is ideal.

 Minimize use of third-party applications:
Excessive use of applications LIke games that prevent the screen from dimming or shutting off or applications that use location services can reduce battery life.

 Don’t keep it packed :
Your device needs some fresh air while  charging.

 Use iPhone Regularly:
it’s important to keep the electrons in it moving occasionally For proper maintenance of a lithium-based battery.