Easy
This could be caused by many things, a couple of which are:
1. If you imported different songs from the same album at different times, some iPods display them as two or three different albums.
2. The artists name, the album artists name, or album title and track number are factors. In case of artist name, check to see if there are any spaces before or after the name. In iTunes, even if you accidentally press the space bar after the name, it counts as a character.
Those are the the main factors. Hope it helps.😉