I'm still a rookie bassist, but I've been playing for a few months with a rock guitarist and drummer on some of the guitarist's original songs. Most (OK, all) of his songs are major chords. He doesn't know much about music -- like what key the song is in, for example. I've pretty much settled on simply following his chords, but I'd like to vary things a bit. Any suggestions? Forgive me if this post sounds simplistic. I'm new at the bass.