A songwriter is a storyteller. To be good needs to study the craft of storytelling/songwriting. In this sense as detached onlooker and student.
Also to to read a lot
Watch films
listen to many different people's music
To observe the world around them. From conversations overheard on the street, family experiences, friends tales.
To practice developing their own style of writing.
To be aware of their own emotional responses to what life brings them.
I think Morrissey's writing is a mixture of storytelling and his own understanding of what happens to him and how he deals with it.
Morrissey writes songs on many topics
love, desire, sadness, murder, the meaning of life, anger at injustice, complaint against authority figures, death, crime, obsession - a wider range than most songwriters I can think of.
But how many has he written on "I'm sorry, I didn't mean to hurt you"
or "This conflict was hard to deal with but has strengthened our relationship"?
This does not mean he has no experience of these, but chooses to write about other things.
This is what sets him apart from the more traditional pop song writers.
However, though I enjoy listening to Morrissey I also enjoy to other artists on their own terms. "Ruby" for example, is a great pop song and one of my favourites from last year.