Brightness: Dim the screen to the lowest comfortable level to achieve maximum battery life. For instance, when watching a DVD you may not neet full brightness if all the lights are down.
Airport Wireless: AirPort consumes power, even if you’re not using its features to connect to a network. You can turn it off in the taskbar to save power.
Bluetooth Wireless: Even when you are not using Bluetooth it still consumes power. You can turn it off in the taskbar to save power.
Applications and Peripherals: Disconnect peripherals and quit applications not in use. Eject CDs and DVDs if not currently accessing them.
For more information please go to http://www.apple.com/batteries/