Well... for general song lyric language features, you should see
Rhyme and rhythm patterns
Verse to chorus structure
If you notice any important pitch and tone changes in the music
Contrasts in lyrical text
And as a general rule, when you're relating to stimulus texts, you have to pick out the main meaning in your text and the main meaning in the stimulus material and compare/contrast how each of the texts makes those meanings.
For example, (text 1)'s main meaning is that it is the journey and not the destination that matters, and it shows this through the juxtaposition between Gwen's bitter dialogue in Act 1 Scene 2, and her silence from Act 4 onwards. (Text 2)'s main meaning is that the destination is what is important, and it shows this through the erratic rhythmic patterns only softening once the persona has reached her target.