iPod from our chat room writes:

I have some tips on keeping your iPod battery alive as long as possible (because we all hate the day where we have to replace it).

1. Dont keep your screen too bright! 50% brightness is a decent level. You don’t need it at a high level just to listen to music, even watching movies it should not be too bright. This tends to wear down the battery very quickly, as it is a major part causing iPod or iPhone battery to run out

2. If it’s on a dock, turn it down. Turn the volume down pretty low, but turn your dock up high. This saves battery life, because it takes lots of battery to keep the volume high — the same if you’re listening to your iPod with headphones. Don’t keep it too high. Set a volume limit for your needs, and for the sake of your battery.
3. When you power down, turn the hold switch on. This prevents unwanted power-ups and playing unwanted music or videos. Obviously if its turned on, it’s going to wear down its battery. Enforce this especially if you’re on a long trip with no USB port close by.
4. If it’s in a case, take it out when it’s connected via USB. Your iPod or iPhone will warm up and this would wear down the battery, speeding up the time until the battery fully dies. If it’s just a case that is meant for not getting scratches on your iPod, then that’s okay because there usually thin and have spaces for air to escape.