Could be any number of things - we'd probably need a bit more info.
Depending on which Wildfire it is and whether or not it's new, the battery could be coming up for 3 years old. May be that it needs to be replaced - batteries do wear out.
You probably also need to optimise your battery usage. This is mostly fairly obvious stuff like:
Find the Power Widget (it's a standard Android widget so you do have it) and drop it on a home screen. This lets you switch off heavy battery users like WiFi, Bluetooth, GPS and Sync when you're not using them. You probably also want to keep the screen brightness set to auto.
Turn off location services and Google Now, if you have them.
Reduce the number of apps that sync (Facebook, Twitter, e-mail, Weather, News etc) and / or the frequency that they sync.
Reduce the timeout time for the screen.
