You know what helped kick my battery into gear? I drained to zero, and every time I turned the phone back on it would have some ridiculous 16% charge left. So I did the back and forth of letting it die, turning it back on about three times and then I did a full charge. I also turned off that option in the advanced wifi settings to "send information about Wi-Fi connections to help discover nearby Wi-Fi".
I also try and do a healthy mix of both wireless charging and USB charging to get the battery used to the mix. I noticed my battery life doesn't last as long on a wireless charge so that's when I started mixing it up... it seems better so far.
Install a good battery app such as battery sense (
Battery Sense | Windows Phone Apps+Games Store (United States)). That app monitors your battery history and records it, such as longest battery life, current % of battery drain, time to charge, etc. The app is also completely free with no ads... with an option to pay if you want to donate to the developer. My phone was consistently draining at over 6-8% an hour ON IDLE (i.e. Just sitting at my bedside for hours not being touched), and yes sometimes I would have it bad such as a 40% drain within 30 minutes (i.e. battery at 45%, suddenly I'm at a critical 5% and it needs to shut off soon).
The last several days I've been getting 24hour+ battery life so I must have done something right. My battery drain is now usually at anywhere between 0.6% to 1.9% now.. unless I've been heavily using the phone. All I did was do the "let it die and turn it on" cycle three times one time, let it die normally three separate times and charged to 100% using USB twice, wireless once, and I try to take my phone off the charger as soon as I notice it's at 100%. I usually charge via USB a few hours before bed, so I won't let it overcharge. Sometimes I've had to charge on wireless overnight, but if I happen to wake up for whatever reason and notice the charging light on my stand is off, I remove the phone.
Also, email syncing... I have two exchange accounts set to "sync items as they arrive" - my outlook.com email, and my school email. I heard that saves battery. My google mail is set to sync every 2 hours since it's not exchange. I suppose I could always forward google to outlook and could save some battery maybe, but I don't want the garbage from my gmail in my outlook inbox.