Many ways to save battery, but first. If you have wifi on and connect to your wifi network, the mobile data is overridden and wifi is used for as long as it's in range. As soon as you lose the wifi signal 3G/4G kicks back in.
Other ways to save battery:
Use a dark/black wallpaper
Don't use live wallpapers
Use power saving mode
Turn off haptic feedback or customise it so only chosen apps use it.
Set sync settings for email accounts with peak/off peak settings
Lower the brightness of the screen (20% does me)
Turn off any unused 'motion' settings
Turn off NFC if you don't use it
Turn off location & wireless networks if you don't use it/need it.
Turn off smart stay if you don't use it.
Set screen timeout to turn off quicker.
Turn off the softkey lights
Turn off auto screen tone
Try an alternative launcher instead of touchwiz (many use less resources or are more efficient I believe)
Don't use widgets that poll the internet or change the update frequency.
There's a start, I'm sure there are more things you can do, and if you root you can run custom kernels that are much leaner and streamlined along with access to apps that can customise your CPU frequency for different states, idle/sleep/awake/games etc.
Enjoy.