Completely new to Android, but have found several things in the past few days:
I disabled background data, added a widget for mobile network (which I toggle on/off as needed, this comes on quickly when needed) and this has really, REALLY improved my battery life. From 8-10 hours...to 20 hours today, and counting. Battery is still at 3/10 bars. Up time is 20:00:00, awake 4:22:20. Yes, I haven't been on the phone that much today, but still it is much improved. Wi-fi when at all possible, otherwise off. No 4G in my area, so always off. And GPS off. No task killer program running.
Although, it seems senseless to have to toggle mobile network capabilities off/on, if you really need to maintain battery power, this seems to be the way to go. Certainly an extra battery is an option, but while you're waiting for it to come in the mail, this may help!