I have a different phone (dual core, 4.5 inch screen) but here is how I make my battery last a long time...
On my phone it's email and social apps that suck the battery so I did this...
1. I don't need immediate email on my phone. I installed no email apps and I disabled the sync of of the Gmail app. If I really need to check or send mail on my phone I now need to use a browser and go to the email website to do it. That is fine with me.
2. I have minimal social apps, but to shut them up I leave my Wifi and Cell Data OFF on my phone all of the time except when I need one of those connections. I also leave off GPS, Bluetooth (and Location Services set to battery saving).
3. I turn off all vibration aka haptic feedback in sound and keyboard settings. I also turn off audible feedback when I can. I don't need a beep or buzz every time I touch a keyboard key or long-press an icon.
4. I keep my screen brightness fairly low, I do not use Live wallpaper - I use a fairly dark non-Live wallpaper. I also do not use any third party launchers.
5. I make sure the Google Play app's own menu settings are set to only update apps over Wifi. When I charge my phone, when the phone is 60% or better, I connect to Wifi, go to Google Play, left upper app menu, My Apps and do Update All. That way all apps that need updates get them while I am connected to power. When the updates are done and the phone battery at 100%, I turn off Wifi and unplug the phone.
6. I avoid piggish apps. I check in Settings..Apps..Running and I look for apps that I INSTALLED that are running when I personally did not start them. Then I decide if I really need that app. Kindle Reader was one that always runs itself - I uninstalled it and just have a simple reader now with some free classics in case I actually want to read on my phone. I leave the Google Apps alone and just uninstall ones I added to the phone that won't stay asleep. I only keep a few I really want that don't waste battery when Wifi and Cell Data are off.
I am a light phone user - few calls or texts per week and just a bit of browsing if I eat lunch somewhere with Wifi. My battery charge lasts over a week. Typically, every Monday when I charge I have over 50% battery remaining.