I've just switched to a Lumia 930 from an android phone, and have to say I was a little disappointed with the battery life in standby, especially overnight. The phone was losing between 10%-15% charge overnight, compared to just 3-4% for my android device.
I've had a look online at various forums, and was glad to see that it wasn't just me! Anyway, i've made some very minor changes and now my 930 only drains 3-5% overnight, which is much more acceptable!
Initially, I went through which apps were using battery in the background and disabled ones that are of no real use/interest to me. Then I changed my email account to sync every 2 hours instead of the 'based on my usage' setting. These both helped, but the drain was still around 10%. I also noticed that it drained steadily through the day. That was until yesterday, when I checked my phone whilst in work at around 11am, and the battery had plummeted to 31% in just 5 hours. I also noticed a little circular icon in the status bar, which I later discovered was location services. Now i'd read that Windows Phone only uses your location when an app requests it, rather than keeping it on all the time - but for some reason, it was continually using my location for something. After turning location off (i have added it as a quick toggle in Action centre now), and recharging my phone, the nightly (and daily) standby battery drain is between 3% and 5%.
I hope sharing this may help some of you guys!