Turn off bluetooth, gps, wifi, auto sync, and the "scanning always availible option" for your wifi when not in use. The weird thing with wifi here is that it is almost always checking to see where you are to assist with gps functions. If you're looking for an app, I suggest "Deep Sleep Battery Saver" which puts your device in a "sleep-like" state while the screen is off meaning that it will do what it usually does more intermittently than it usually does.