Adjust Your Device's Settings

• A bright screen drains battery power, so turn down the brightness in your "Settings" menu. Also, adjust your autolock settings to one minute. Autolock turn off the screen after a specified period of inactivity, thereby saving your battery's charge and limiting the number of times you accidentally tap the screen and initiate other battery-draining activities. Don't worry, you can still receive calls. Finally, set your phone to "Airplane Mode" when in no-coverage areas. This prevents your device from constantly trying to establish a connection with a cellular network. In airplane mode, you cannot make or receive calls.
  
  

Adjust Your Network Settings

• Many applications access the Internet on a regular basis to check for new data. Examples of applications that do this include the email application, news applications and social networking applications. To reduce the burden this process places on your battery, tap on "Fetch New Data" in the "Mail, Contacts, Calendars" section of the "Settings" menu, and reduce the frequency of data fetching. Also, if you are not using the Internet you might want to turn off your Wi-Fi. Otherwise, your device will constantly be searching for new signals. You can turn off your Wi-Fi from the "Settings" menu. However, if you are using the Internet and Wi-Fi is available to you, you should keep it on, as Wi-Fi requires less battery power than cellular data networks require.
  
  

Change the Way You Use Your Device

• The use of any application drains your battery faster than when you aren't using it, but some applications are far worse than others. Any application with 3D graphics, especially 3D games, requires a lot of battery power. Applications and games that require consistent vibrating and those that use GPS tracking are also battery-drainers, so reduce your use of them when you need your phone to stay on all day.
  
  

Maintain Your Battery

• To preserve the lifespan of lithium-based batteries, the electrons within it need to keep moving. This means using your device on a daily basis and going through one or more charge cycles per month. A charge cycle is when your device is fully charged then allowed to lose its charge completely.