Connect your iPod to your computer and then open iTunes.
Click the drop-down arrow to the left of the name of your iPod beneath Devices on the left side of the iTunes program window.
Click the name of the playlist that you would like to change.
Be sure that the "Shuffle" button in the lower left corner of the iTunes program window is turned off. The Shuffle button comprises two overlapping arrows, and is blue when the feature is enabled and grayed-out when the feature is disabled.
Click the name of one of the songs you want to move, and hold the mouse button down.
Move the cursor slightly to reveal a black line either above or below the song, which indicates where it will be placed in the playlist order if you were to release the mouse button at that moment. Continue moving the cursor until the black line is located where you want to move the song, then release the mouse button. The song will appear in its new location, and the playlist will quickly re-sync with your iPod.
Repeat Steps 5 and 6 until you are satisfied with the new order of songs in your playlist.
Click the "Eject" button to the right of the name of your iPod once you have finished making changes to the playlist. After the name of your device disappears from the list, you can safely disconnect it from your computer.