Just a short and conclusive post.
1. Adjust Screen Setting
That's including the Brightness, and also Screen Timeout.
For Brightness, adjust it to your current environment lighting for example during the day, under the sun, or at beach; until your eyes comfortable with it, its no use if use low-light but u can't read them. OR just set it to automatic brightness where the machine will automatically adjust the brightness according to the current ambient light it exposed to.
Screen timeout is also important, kindly adjust it's timeout accordingly, if you wanna use to reading books u maybe need a longer timeout (i.e 1 minute) or it will off the light but u still didn't finished the page. If u just use it for a normal use just set it to 15-30 secs, since it still not turned-off screen when u still using it (active).
SETTING > DISPLAY > BRIGHTNESS/SCREEN TIMEOUT
2. Set hardware, software, apps when not in use
Wifi, Bluetooth, GPS; Kindly switch off when not in use. For Synchronization, the advice is it should not be set 'ON' when not in needed since it will running all the times and updating 24/7, just turn it ON and sync when needed.
If you are in offshore or other places that have no phone line, or u don't want to be disturb. Just turn the phone to 'airplane mode', if not the machine will just still running the cellular mode even u are not using it. You can set to airplane mode by hold the power button, the option will pop-out.
Maybe you should not set all your apps to automatically update, the one that require constant updating should be set to manual update.
3. Limit background Application
In some android OS, you can set the background apps limit.
SETTING > DEVELOPER OPTIONS
DON'T set the background process limit below 3 since it will reduce the machine efficiency. If you have the option 'Don't keep activities' just tick that, it will reduce some battery consumption. After done using your tab, or smartphones, just kill them by go to Active Applications tab, kill any unused application and clear the memory once in a while under the RAM tab.
4. Set *still wallpaper instead of *live wallpaper
Kindly note that live wallpaper drain your battery when it's in use just because its LIVE. Just have a suitable photo to make your wallpaper
5. Monitor battery usage once in a while
You can monitor all your battery usage from
SETTINGS > BATTERY
If abnormal battery usage and application that use a lot of energy, its your call to remove it from your system or let it running.
Last but not the least, IF you want an even longer battery life but don't wanna set the setting, the advice is to buy 3310 NOKIA with torch light. haha. Have a good day guys.