Welcome to AC!!
There is lots of easy things to do to increase battery life. Turn of live wallpapers, decrease sync times for apps, turn of 4G when not in use (though I couldn't figure out how to do this on a co-workers S3), keep Bluetooth and WiFi turned off when not in use. You can use battery management apps, but, I have not found a need to thus far. I usually get through the day without having to charge.