If you are dealing with writers and poets, you might want to take some time to examine (in some challenging and creative way) the differences between song lyrics and poetry. While it is true that some poetry sings beautifully, some does not. And conversely (as Jerry has said), some very effective song lyrics don't make great poetry sans tune. Why so?

And one sometimes-interesting way to explore the relationship between text and tune is to find a text that has been set to different tunes
(or a tune that has been used for different texts) and to ask which setting is more effective and why.