Not sure what I did, but I've been off charger for 30 hours now and still have 39% battery. This is with moderate to light use.
When I initially got the phone I never fully charged or discharged for the first couple of days, I kept it in the 30% to 70% charge range. I did use it heavily during those days. I gave it the first full charge two nights ago, it's been off charger since about 10am yesterday (it's 4pm here now).
I also turned off many background and notifications for apps. The only major difference is that I turned and left on Bluetooth the past 2 or 3 days.