here are some tips to prolonged battery usage
Data/Network Signal - If necessary, always use 4g/3g/2g indoors. if you lock your data to 4g or 3g and signal is poor, the phone will search hard for a good reception. And the hardware of your AF2 will work and consume on your battery
Widgets/Live Wallpapers - this one runs even your phone is idle.
Weather/Location - turn off if not needed
Apps - check whats running @ settings>apps>running. If you see some apps that wasn't helpful for you, just disable it @ settings>apps>all and find the said app. Also always use click clear app if you will idle your af2
Also check apps that use proximity sensors. It drains your battery too.
Background Process - if your not a multi tasker, this one is helpful. Just go to developer option>background process limit and set it on 4 background process (or as you what prefer). This will limit the apps running in background while idle or using it.
I refer greenify app for saving battery usage. Don't install any battery saver, also uninstall avg app, coz android are virus-free coz it is a linux-based unless you are rooted. if you'll install 3rd party apps like messaging, camera, launcher, etc., disabled the stock(original installed) app one.
Hope this will help