whats your display at? if its on auto take it off of auto and turn down to as low as you can stand and add around 5% to that(so your not straining your eyes). then to the cm setting in the settings menu, then to interface, then notif. power widget, then widget buttons, then make a widget for screen brightness, then go to brightness modes and pick how you would like the widget to work. i have mine set to auto,25% and 100%. i keep it at 25% 99% of the time. but this makes it so its easy to turn up and down the display brightness on the fly when needed.
I usually get 20 hours out of my battery(when im at home, due to me being always on wifi) and on days i work i get around 17 hours both with normal-moderate use.
right now im at 14hours on my battery and its at 40%
so for me...i never worry about my phones battery. i charge every night so im always full up. Also this is with me being overclocked @ 1.390ghz, but im also undervolted at 300mhz at 14v.
I recommend Quickclock, for all of your over clocking and undervolting needs. also jakesbitmodv9 and v6 supercharger.
also make sure you properly calibrate your battery. charge to 100%, calibrate then let it die and then charge to 100% and your good to go!
what i did to calibrate my battery was to charge to 100 then go into recovery, then to advanced and i cleared battery stats and then i calibrated(kept it plugged in till i seen the highest mV for me it was 4186mV, your value will vary) . let it die, charged to 100, let it die then charge to 100, and thats all.
i used to be getting bad battery life, so that why i went to such "extremes" to fix it.