Kill any apps that connect to the net on their own and update stuff, most apps you install give you the choice on wether or not you want them to update on their own or you can manually update them, if their not REALLY needed to update and you can live with updating manually do so, I use my BB all day long and my battery lasts at LEAST 3 days before a charge is needed.
Facebook only acesses the net when YOU axxs it, so if your on facebook all the time expect the drainage, while I do have facebook on my BB I never really use it, it does nothing if you don't actually open it and post/read things, all it does is hijack your email that you would normally be getting from facebook and assign a "nifty" lil icon to it lol so all the theorys of it being a "battery drainer" are unfounded, if you use it alot..then ya..if you just have it installed it will cause no drainage whatsoever.
but if you want a phone that does everything...excuse me a DEVICE that does everything...its going to suck up some juice...keep an extra battery handy...
besides if you are calling from hawaii thats like really far and uses more energy...haha just kidding
I also think that the battery improves over time. I have noticed much longer battery life now, after a little over a months use, than I did during the first week of ownership.
And...I agree with an above poster, in that long-distance conversations are the biggest battery drainer of the bunch by a long shot. Most of my close friends still live in Texas, and the main reason I have ordered a Seidio 1500mAh battery is because of them...or at least because our conversations effectively kill my battery after a few calls.
Many 3rd party applications do not stop using the battery if you simply back out of them (by pressing the Escape key or the red end button).
For exmaple, BBWeather continues to run in the background and will also use up memory if you just close out of it. You should always click the menu button and EXIT and it will stop running. Many other apps are like that, too - Google Maps, Gmail, etc.
A Blackberry or any cell phone constantly connecting to a weak signal will drain a battery a whole lot faster. The weaker the signal from the cell tower, the more power your Blackberry will use to try to connect to it.
FYI: The transmission power in the handset is limited to a maximum of 2 watts in GSM850/900 and 1 watt in GSM1800/1900.
Surprised no one mentioned IM apps. When running (even in background), they are constantly connecting to servers to update status or get new messages. Definitely something that will hammer the battery.
Poor signal (already mentioned) is the biggest battery flattener.
bluetooth
general use - especially phone calls (sorry)
watching movies - it's the screen lit up.
Charging via the original BlackBerry wall charger is generally accepted as being the best way to obtain top battery use - it was designed to do just that.
I bought a couple of spare batteries from ebay and I kep one in the car and one in my brief case.
Doing this is not really reccomended from a battery perspective since Li-ion cells do have a limited shelf life but they were cheap and this practise does get me out of trouble.
I have noticed on my Sprint 8330 that having the TV on will drain it rapidly. Even if you are not runing a station and it is sitting in the background. When i am not running TV I can run it all day on one charge but only 3 hours with TV running. Also, built in Blackberry apps do not close in App switcher. Any other way to close them?