Just managed to pull 12 hours of usage this time. What I changed from how I've used my phone going back to the 5S is, turned off push email and went back to manual, turned off all push notifications except for phone and text messages (previously only used it for Facebook, Twitter, Instagram and snapchat), and lowered brightness down from 80% to around 40%. I also keep background app refresh off and location services are only on for apple/Google maps, tinker per and Siri and are only set to be in use if the app is open.
These tweaks definitely made a difference as before I was getting 7-9 hours on average. Yesterday when I was still at 100% and 15 minutes of usage I went for a 45 minute walk with runkeeper active and using gps and streaming a podcast over lte through my Bluetooth headset. When I got home the battery was still at 100%. Same thing today, left house at 28% and came back 40 minutes later at 25% though it stayed at 28 the majority of the time. It good to see GPS isn't being a drain so far.
I'll probably keep everything the way it is for now just to see if everything stays consistent as far as usage times. I expect if I get longer standby that usage may decrease slightly but still better than what I started out with.
As you see I did a lot of YouTube video and streaming probably 3 hours or so of podcasts with the screen off. Also did some light to moderate gaming and some texting along with social media and a single phone call. I may activate push notifications again in a week or two to see if that was causing any noticeable drain. Probably not since Saturday night I didn't lose a single percent in 7 hours though emails and Facebook messages came in a lot. Last night with all that off again not a single percent lost.
I've never been a complainer of iPhone battery except when I had the 3GS and AT&T had poor signal in my area. Always used to 4-5 hours of usage over a day and a half of standby so with the 6 plus it's way more than I could ask for. Couldn't be happier at this point.