(cellphones used here are Samsung galaxy s2 galaxy y)
1. Switch off wifi and Bluetooth and 3g if not in use.
2.keep you display to less than 30 % to increase battery life. Never use juice defender or battery saving apps as they interfere with your data connectivity.
3. Decrease the number of screen widgets u r using.. Delete those empty home screens decreases battery usage greatly.
Is a boon but a battery hog
Just go to settings account sync and switch off the auto sync for most of youe accouncts except your email if u use it alot. Of fb gadget as you wish. But yes decreasing the auto sync feature greatly increasea your battery life
5.let your phone completely charge and then discharge to the fullest extent this will make your battery live longer.
6. Decrease your vibration intensity, i.e you haptic feedback by going to settings sound uncheck haptic feedback.
7. Kill the unnecessary apps running in back ground either u can use the task manager or use go launcher and selectively kill the apps.
8. Decrease the screen timeout to 30 sec maximum.
9.switch off your phone once in a day.
10. Go to settings storage clear cache. Or use apptosd app to clear all app cache make phone faster
11. Screen shot
Press home key then immediately+power button