hmmm i would suggest do a re-install, and during the setup wizard select as wifi-only (turn mobile data back on later), then once booted make some changes in settings.. screen brightness, animations (i always turn them off but some people CARE) lol and any other useless ui tweaks off that drain battery...
also once your signed into google, go to your sync settings and uncheck everything you dont use... turn off word completion and suggestions in keyboard settings (unless you actually use that crap

j/k)
uhhhhmmmmm another thing is remove any un-used 'screens' on your device, i keep like 3 MAX
now my personal favorite (because sooo many people seem to hate this)
ATK!!! lol not sure why people hate it... you dont need to use the auto-kill option, i dont. i just enjoy having the widget on-screen to tap & kill background crap... (every once in a while i go to setings and set security to low then perform a 'kill'.. it kills more background data than it should but youll notice your available ram jump from like 160 to 250, then set it back to high or medium...)
I personally LOVE that app(ATK), i dont use ANY features in rom toolbox but people seem to like it better so i keep it on for them... but i personally think its unneccesary to OC this device, and that app has way more crap on it so im sure its more of an issue than atk will ever be!!