Iphone 4 battery draining quickly

When i bought it a few days ago, my battery was great and lasted long (1.5 days)… As of last night, it keeps losing 10% every hour on standby and not doing anything…

just wondering what's going on? Should i restart it (not just turn it off)? And if so, how do i do that?

i've been doing things such as turning wi-fi and bluetooth off, using auto-brightness, turning off location services and push notifications… I also don't have a lot of apps. Just the normal social networking ones. And i don't call/text that much.

any tips or advice? I'm worried because it seems worse than my blackberry.

should i just follow this guide? Legit or no? Http://www.gottabemobile.com/2012/05/21/how-to-fix-bad-iphone-battery-life-on-ios-5-1-1-in-5-minutes/

Added (1). I'm using the iOS 5.1.1

There are apps you can get to turn off all of your apps when your not using them. Your apps also collect cache which you probably should clear ever once in a while. If your Wi-Fi is on it could also drain your battery along with your GPS.

One problem may be your carrier. If your carrier has very few towers in the area, your phone is constantly searching for signal and that will drain the battery fast. I would suggest a restart ( hold down the power button on top of the phone until the screen asks you to slide the arrow for power off. Then hold down the same button until you see the apple.) If that doesn't work, take it back to the store you bought it from and let them kknow what problem you are having.