Turn your screen brightness down to as low of a level you are happy with. The lower, the better.
Turn OFF Bluetooth if you aren't using it
Turn OFF push notifications if you don't need them o want them.
Turn OFF Location services if you don't need them for a specific reason.
Turn the "sleep" waiting time down to two minutes or five minutes.
Turn OFF WiFi if you don't need it.
I also suggest letting the battery go down to almost zero% every month or so which will ensure that meters accurate. Otherwise, just keep it charged up and enjoy. I've found the battery life on my iPad 2 quite excellent!