1. Use LTE Only When Needed
Never use LTE if you're not using it at all and select 3G instead. 4G/LTE features high-speed mobile data connection but eats a lot on the battery more than you think than 3G.
2. Selective Features
Features are amazing and may actually help you every day but not all of them are good for the battery. Keep those features you use at all times and turn off others which are not needed on every day activities.
3. Wireless Connectivity
Aside from mobile data, watch out for other wireless radios such as Wi-Fi, Bluetooth and NFC which consumes power and you must turn them off whenever not in use.
4. Preferred Internet Connection
Whenever there is an available and decent Internet connection via Wi-Fi, use it instead of mobile data to preserve power on your phone.
5. Display Screen
Around 50 per cent of power consumption is allocated on the screen which means you need to manually set the brightness level comfortable to you, minimise screen timeout and use static yet dark wallpapers to save energy on the display.
6. Location Services
GPS can kill your battery life and set only certain apps allowed to use location services - those which requires it.
7. Apps and Widgets
Widgets are good display designs on the home screen but only a few helps your battery. Remove widgets you're not using anymore and uninstall the app altogether. In addition, be careful with certain apps which are poorly written that may eat away battery faster or damage system files on the worst part.
8. Don't Forget This!
Samsung installed a non-removable Power Saver on your Galaxy S3 and you should use it as much as needed. Whenever you are not using any Internet connection or high tasking services, activate the Power Saver from the notifications shade to manage battery life better.
9. Colour Profile
Galaxy S3 features screen mode and you should use customise the profile to help save power consumption on the Super AMOLED display screen.
10. Refresh Regularly
It is recommended to restart your phone once a day to refresh the entire system after an entire day of full work just like a computer. It will also help the memory to perform better after a reboot.
11. Factory Reset
In worst case scenario of apps damaging the system, you'll need to reset the smartphone. It will restore the default apps and remove all other culprits which may have caused the battery last shorter and poor performance on the phone.
12. Drain the Battery
Certain times require battery drain similar with laptops and notebooks to enabling healthy charging cycle. Usually, battery draining a device once a month then getting a full charge for about four hours keep cycles healthy than those units without recharging cycle.
13. Avoid High Temperature
Avoid leaving the phone inside your car or putting it on a surface with direct sunlight to prevent damaging its battery. High temperature will damage the battery pack leading to poor performance. However, extreme cold can also affect the device leading to moisture damage.
14. Root Access
Rooting will void the warranty but if it's already gone, why not do it anyway. Root access will enable you to control various aspect on the battery and processor to improve power management.
15. Custom ROMs
Samsung Galaxy S apps and TouchWiz UI consume high amount of battery which makes other Galaxy S3 users to resort on custom ROMs. Custom ROMs always feature better power management, CPU tweaking and larger memory compared to stock ROM and if you want longer battery life, get a custom ROM.