- You can turn bluetooth (if that's a feature), GPS and Wi-Fi off. The sync functionality also uses up some battery.
- Close any apps that run silently in the background using the Android task manager or power control feature.
- Disable the vibration feature.
- Remove any active animated wallpapers if you're using any. They take up a bit more juice for the pretty look =/
- Set a timeout interval - the display pulls a lot of your battery power. Turning it off when not using it helps.
Of course, only disable what's not convenient for you to save the extra battery life.