how to increase battery life?

Are you the kind of person for whom a mobile phone is more than just a necessity and is more of a lifeline? And you wish your battery did not run out on you so often? It is possible to get more out of your battery, you just have to keep a few things in mind.
GET THE MOST FROM YOUR CELL PHONE BATTERY:

Prevent the Memory Effect - Keep the battery healthy by fully charging and then fully discharging it at least once every two to three weeks. Exceptions to the rule are Li-Ion batteries, which do not suffer from the memory effect. Do not leave the battery dormant for long periods of time.
Always use a battery charger, which is by the same manufacturer as your phone, it gives it more life. It also helps if you overcharge your battery now and then.
Keep the Batteries Clean - It's a good idea to clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the portable device.
Do not leave your cell phone near any source of heat, a common place being the dashboard of your car, as extreme heat may affect the battery. The battery also operates better at room temperature, vis-à-vis extreme cold.
The vibrator mode of your cell phone consumes more battery, so when not needed, use the ring-tone mode.
Battery Storage - If you don't plan on using the battery for a month or more, store it in a clean, dry, cool place away from heat and metal objects. Batteries tend to de-charge when not in use, so make sure you charge them again before using. The performance of any cell phone battery, however, no matter how properly cared for, usually diminishes after about a year. It is better to get your battery replaced then.
Related More Information:

"My new battery isn't charging. Is it defective?"