1 word cleanrom.
All I do is connect to wifi whenever possible, I leave everything on 4g/GPS/wifi all the time. I have 4 emails set to 15 minutes during business hours. Over the weekend I got 1 day, 18 hours with 19% left when I plugged in on the standard battery, light use. Like someone else said stop looking at your phone every 3 seconds let it sleep unless you need it or you get a notification/call. Set it to pick up and use any wifi you are around and set wifi NOT to turn off when sleeping, you would think that would save battery but it doesn't it makes your phone use 4g for anything until you turn the screen on again.
There is a very short charge in there which added maybe 5% during a quick car ride. Went from Fri night to Sunday afternoon on the standard battery. Would have gone 48 hours easy.