It's almost always either the screen or radios (2G/3G/wifi) that rinse your battery. Tweak your brightness and perhaps try 'auto mode' if your phone supports it. When your not using it, disable data mode (perhaps the name is slightly different). Power saving mode needs to be explored properly for it to do any good but is not really that useful.
Juicedefender is an app that turns down your brightness, turns off gps, wifi, 3g etc based on a set of rules you define. Something like "When the screen is on, enable mobile data" or "When I have google maps open, enable gps and data". It is pretty unintuitive to use unfortunately but with careful experimentation it does work. I live in an area of awful signal and I loose my battery very quickly when 3G/4G is enabled, the phone spends the whole time searching for signal of for a better signal and uses up a lot of power. Hope this helps.