Update to the latest software

Make sure you have installed the latest version of iPod software.

Use the Hold switch

Set the Hold switch on iPod and its remote to the Hold position whenever you are not using iPod. This will keep iPod from accidentally waking from sleep and playing songs if its buttons are pressed while in a pocket or bag.
Keep iPod at room temperature

iPod's battery works best when iPod is at room temperature, generally near 20° C, but you can use iPod anywhere between 0° to 35° C (about 32° to 95° F). If you have left iPod in the cold, let it warm up to room temperature before waking it from sleep. Otherwise, a low-battery icon may appear and iPod will not wake from sleep. If after warming up, iPod does not wake from sleep, connect the power adapter, and press the Menu and Play/Pause buttons until the Apple logo appears.

* Do not leave iPod in a vehicle's interior when parked in the sun. Temperatures may reach up to 150° F (65 °C).
* Do not leave iPod exposed to direct sunlight for extended periods of time.

Additional tips

Charging

iPod fast-charges the battery to 80 percent of capacity in an hour. However, it can take 4 hours to fully recharge the battery. Even in sleep, iPod uses a small amount of current, and the battery slowly empties. Stored at optimal storage temperature, the battery will empty in 14 to 28 days.

* You should charge iPod when it has fully discharged even if it won't be used right away.

Pause iPod when unattended

If you leave iPod unattended, press Play/Pause to pause the song. If left playing, iPod will continue to play songs until the battery is drained--particularly if the repeat setting is set to One or All. Put iPod to sleep to save battery life. Press the Play button until iPod goes to sleep.
Backlighting

Backlighting can use a lot of battery power. If you don't need to use backlighting, turn it off. Choose Settings > Backlight Timer > Off.
Equalizer

Turning off the Equalizer will extend your battery life. If you don't wish to use the Equalizer turn it off. To turn off the Equalizer, choose Settings > EQ > Off
Avoid changing tracks

Avoid changing tracks by pressing the Previous/Rewind or Next/Fast-forward buttons. If you frequently change tracks by pressing the Previous or Next buttons, iPod has to turn on the hard drive to open the songs. This uses a lot of battery power.
Use compressed songs

iPod's cache works best with songs of average file sizes (less than 9 MB). If your audio files are large or uncompressed (including AIFF format), you may want to compress them, or use a different compression method, such as MP3 or AAC, when importing them into iTunes. Also, consider breaking very long songs or tracks into shorter tracks that have smaller file sizes.