How much do you use it? I typically get about two days out of a charge, but I am a fairly light user. A lot depends on the types of app you have installed. If you have several that require regular sync (e.g. Facebook, Twitter, weather widgets, Gmail) then your phone will rarely enter full sleep mode. If you are really concerned, I would back up your data, perform a factory reset, and just install a couple of apps each day until you find what is draining the battery.
Before that extreme you can try ensuring your Wi-Fi is set to switch off when your screen is off (I think it actually takes about 15mins rather than knocking off immediately the screen goes blank) and just using 2g networks for a few days (I think a lot of battery is lost when the phone is searching for a 3g signal, e.g. when you are driving or in buildings with weak signals).
I presume you have looked in Settings --> Battery to see what has been using the battery and followed the tips?
As far as my own phone is concerned, I use a combination of toggle widgets (Power Toggles) and Tasker to minimise my phone's activity when I am not actually using it. In addition to setting Wi-Fi to sleep when the screen is off, I only switch to a 3g signal when I actually need it (i.e. when I am not at home or work and doing something that absolutely requires a fast connection, which isn't actually all that much). The only things with sync enabled are Gmail and my home email. I guess I should even disable those because I only use them for non-essential things and can check them manually once a day. I use the facebook mobile site rather than have an app constantly checking for new updates; again I only bother checking it once a day). I find the screen (the biggest battery hog) doesn't need to be anywhere near full brightness in most conditions, and usually have it on the minimum setting in the pull-down widget. Again, it is easy to brighten it for the odd occasion it is needed.
I only need GPS enabled for the odd app, so I have it disabled mostly and use Tasker to automatically activate it when I launch an app that needs it. Tasker also activates Bluetooth only during the two times of day I am likely to need it (weekdays, driving to work and riving home again); it is off the rest of the time.
I seem to be getting less time out of my battery since installing HD widgets recently, but it doesn't even show up in Settings --> Battery so that may just be perception.
Edit: I also use Tasker to switch to Airplane mode overnight, when there is absolutely zero point in me knowing about new emails or other updates and where people could phone my land line in an emergency.
Edited by Konstipated Kiwi, 28 January 2013 - 03:05 PM.