Creating an arrangement for your song involves many musical elements which you need to assess. Among these factors you need to experiment with are lyric articulation, dynamics and tempo.
Articulation
Sing through the song as you normally do, noticing the articulation and flow of the melody. Now sing the song again and change the articulation. Make the consonants super crisp and really precise. When you articulate like this, you’re most likely inspired to make precise sounds with your singing voice, similar to classical music.
When you sing the song again, change the articulation so that the consonants and vowels are correct but not so crisp and precise. This laid-back articulation is similar to what happens in a pop song or other contemporary songs that you hear on the radio. You can choose the best articulation for the type or song you’re singing based on how you want to express the story of that song.
Dynamics
When you sing the song this time, sing it loudly. The meaning of the song may change when you sing it loudly. Now sing the song again, but softly. The third time you sing the song, vary the dynamics, singing some sections loudly and others softly. You want to gradually change the volume so your song builds toward the climax.
Tempo
The next element to explore is the tempo. Sing through the song slowly, and then sing through it at a fast tempo. When you’ve explored fast and slow, sing through the song and gradually change the tempo of the song. You can start slowly and gradually speed up, or vice versa — start fast and gradually slow it down.
You want to explore which segments in the song make sense to sing faster and which sections make sense to sing slower. The changes in tempo don’t have to be drastic — just change them enough to keep the song evolving.