iTunes does not sync songs/albums to my iPod Touch correctly, what's wrong?

I have my iPod set to manually manage music and videos and when I drag songs onto it through iTunes, it doesn't show up on my iPod right; like it says "unknown album" or it wont update the name, but shows up perfectly fine in itunes. I don't really know what to do, because I don't have the space to save all my music to my computer anymore ( I never had these issues when I set it to sync everything). Any suggestions?