There are hundreds of threads on this topic, do a couple of searches and you should have all your answers. But yeah, PB_H is right: turn off all non-essential services (Bluetooth, GPS, etc.) and shut down all non-essential background tasks (tap Settings, swipe left, tap Background Tasks). Restart. That should get most of your problem under control.
You'll also find when you search a number of problem apps: some weather apps, early Nokia Drive betas, etc. Uninstall them.
This is what I don't like about this phone, and peoples attitude towards maintaining battery life on it; either the hardware, or the software, or both, clearly have an inherent fault, and people are prepared to pay their hard-earned money for the phone, and then work around the fact it is faulty, to try and mask the faults.
On my 710 and 620, I install what I want, when I want, I run the services I want, when I want, in the 22 months since I got the 710 and the 7 months since I got the 620, I've never once had to think about "closing this service off" or "not running that live tile" in an effort to conserve battery life.
Any Blackberry, Symbian, Android or Apple converts (remember, 99% of users, maybe more, just want a phone that works, and has decent battery life to get them through the day) will be getting a 920 (and it seems the 925 suffers the same issues), and won't have a clue how to resolve these issues, and if they do, they won't be able to use Windows Phone to its full potential, and get the best experience possible from the OS. They will additionally, be ditching the phones, if they can only provide 3 - 5 hours battery life, at best!
You might all be prepared to use phones that you have to molly coddle, and phones that are severely restricted in what you can do with them, but seriously, go and pick up a 520 or 620 (or 625 for that matter) for cheap, or even a WP7 device, and see how much better the experience is, you don't even have to think about what you're installing and what services you have running etc... One word, freedom!
