1. Tell the device to only use 2G networks. (Settings » Wireless controls » Mobile networks » Use only 2G networks) If you do not need access to high speed data, or there is no 3G or 4G network where you live, you can tell Android to only use 2G mobile networks. You will still have access to EDGE network data and WiFi if needed.
2. Reduce the brightness of your display. (Settings » Sound & Display » Brightness) Most people can see an Android display quite well with the backlighting feature turned off. Move the slider all the way to the left, then try using the device that way. If you can't see it well in that setting, move the slider to the right only as far as necessary to view the display comfortably. Alternatively, Auto brightness coupled with power saving mode (found on most Samsung, LG, Sony, and some Motorola devices) will conservatively adjust the display to the surroundings to only the brightness necessary.
3. If your device has an AMOLED screen, always use a black background. AMOLED screens can reduce power usage sevenfold by displaying black instead of white or any other color. When searching on your phone you can also use Black Google Mobile at bGoog.com to get standard Google results (including images) all in black .
4. Set your screen timeout to the shortest length possible. (Settings » Sound & display » Screen timeout) This setting tells the device to turn off the screen after the selected period of inactivity. The shorter the period, the less power your display will use. The setting options vary from phone to phone.
5. Use the Power Control widget. (Home screen » Menu » Add » Widgets » Power control) As of Android 1.6, there is a widget that you can place on any one of your home screens that gives you quick control buttons for WiFi, Bluetooth, GPS, Push sync, and screen brightness (three levels). Use this to control your settings and turn them off to save battery power, as stated above. This is a nice easy shortcut.
6. Do not leave applications running when you don't need them. Close them and return to the home screen.
7. Switch of wi-fi, bluetooth, data networks when not in use since they consume battery while searching for signals.
The top free power management apps available in the google play are :
