Hey, ok def this battery isn't as good as some, but like always there are tons of ways to help you out.
1st: The higher the back light, the more battery usage.
2nd: Well these days most Cell phone Providers(Rogers,At&t,Etc) are 3G, 3G uses alot of battery because its pulling in more in a basic way to explain that. A way to turn your 3G off while your not using it, is to: Access the Engineering Menu which you can find on this site, then go to MODEM SETTING, next you go to NETWORK MODE then AGAIN NETWORK MODE then change to 2G. It saves a ton of battery.
3rd: The Mobile internet uses battery like a fat person eats, which is alot!!

So basiclly dont use it like 24/7.
Hope i helped a bit Thanks