I think every song/songwriter is created differently.
I can usually churn out roughs in minutes and most of them do need refining. Some I have worked on for over a year because I can't seem to fully transmit the emotion or idea. I have hooks that flow easily into lyrics and then there are some that are great hooks that have potential but leave me drawing a blank!
Then I have to also find a way to share the melody I like to accompany each song and the process above is repeated. Because I cant sing or play any instruments, I must record my mental melody and allow composers to fill in the blanks.
Just my thoughts, hope you have great success!