There are several things you can do, but they will affect the "enjoyment" factor of the phone.
Turn off push notifications. manually fetch email
Take everything out of the notification center
Turn off bluetooth
turn off any location services you don't need
Turn off all system services (you will have to leave traffic on if you want to use it though)
turn off frequency locations
turn off app refresh
turn off sending data to Apple
Those are just a few. There are several threads on this forum that talk about battery life.