Don, good advice above.

I always read before I go to sleep,
and I snore all night, no need for sheep,
I awake in the morning totally refreshed
which annoys the wife as I get dressed.

That's not a good example but I found jotting down stupid little rhymes like that seemed to develope into songs. I write down headlines from newspapers that catch my eye, I always have a thesaurus by my side next to the rhyming dictionary. I used to write my lyrics to songs I liked and found writing 12 bar type songs helped with the flow of words.
It doesn't happen immediately tho' and I have hundreds of scraps of paper, pre computer days, and txt files with sentences that I randomly look at now, when stuck for words.

Fire up BIAB, find a style you like, randomly input chords and repeat as necessary while saying, singing, thinking words that pop up in your head. The initial ones may be awful but then you can fine tune them when you find a tune/chord sequence you like.

One of my Dad's friends, a jazz pianist, told me not to try to hard and if a song is there it will soon appear but don't expect to write "Yesterday" at the 1st attempt. Also Paul McCartney apparently said that the 1st words to that song were "scrambled eggs"

Have fun
Alyn