Today's method to increase battery life: turn off the Wi-Fi.

I fully understand that when you're in a power-outage situation, or just a long car trip, that you want to play games with the other people around you.

But, using that extra feature puts a bit of strain on the battery, and will cause it to run down faster. Not such a big deal if you have a power source handy, but once power becomes a limited resource, then you're going to want every second of power you can have.