How to Make Your Cell Phone Battery Last Longer

1. Turn the phone off. This is probably the most effective and simplest way of conserving your battery’s power. If you don't plan on answering the phone while you're sleeping or after business hours, just turn it off.
2. Stop searching for a signal. When you are in an area with poor or no signal, your phone will constantly look for a better connection, and will use up all your power doing so. This is easily understood if you have ever forgotten to turn off your phone on a flight.
   
3. Switch off the vibrate function on your phone, and use just the ring tone instead. The vibrate function uses up a lot of battery power. Keep the ring tone volume as low as possible.
4. Turn off your phone's back light. The back light is what makes the phone easier to read in bright light or outside. However, the light also uses battery power. If you can get by without it, your battery will last longer.
   
5. Avoid using unnecessary features. If you know it will be a while before your phone’s next charge, don’t use the camera or connect to the Internet. Flash photography can drain your battery especially quickly. If your phone has bluetooth capability, disable it when not in use.
6. Keep calls short. This is obvious, but how many times have you heard someone on their mobile phone say, "I think my battery’s dying," and then continue their conversation for several minutes? Sometimes, the dying battery is just an excuse to get off the phone (and a good one, at that), but if you really need to conserve the battery, limit your talk time.
7. Turn off Bluetooth. BT will drain your battery very quickly, and having it on can cause you problems near virus-infected smartphones.
8. Same goes for WIFI and GPS if your phone has these features built in. Keep them off, save more power.
9. Use GSM - Using your phone in 3G / Dual Mode will drain the battery quicker than if you just use GSM mode - have a look at your phones spec and you'll see it will quote two different battery life times - normally 50% more for pure GSM use.