Its all there in the lyric.
Speak the lyric out loud. Pay close attention to the punctuation. What are the words saying?
Who are you? What do you want? How old are you? What is your mood? These are all things you need to decide. There are many other questions of this basic type to ask yourself. One clue, you are singing the song to yourself.
These are things you need to do with every song you sing.
Can the accompanist play the song? If it is a killer to sing, imagine what it is like to sight read.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher