Lyrics, like all other forms of artistic expression, grow out of an original inspiring feeling. They often carry a single or multiple meme throughout but it is rare that one finds lyrics directly responding to or describing any single situation.
Unlike poetry (which is usually freeform or, strictly speaking. meterless ungrammatical prose with odd linebreaks in this day and age at least), lyrics are usually adulterated from their original inspiration by the second creative input, in this case, melody. A lyric must meet conditions which inevitably make it harder work than just writing down what one may or may not feel.
A lyric without a melody is hardly worth the bother of recording; a lyric applied to a melody takes on shades of meaning and alterations of form which mirror and match that melody.
All in all, it's a fuzzy process. For this lyricist at least, the sequence of events is usually as follows.
Note the rhyme, hook or feeling that inspired the lyric
- Compose an acceptable rhyming scheme
- Determine a melody line based on #1. Note that an exceptionally strong lyric can cause a jazz-like deformation of the melody just as an exceptionally strong melody may warrant a change to #2
- Plot out the course of the lyric, pick the bridging lines, reword and rework as necessary
- Try singing the lyric to the melody. At this point, further alterations are made.
- Repeat steps 3-5 until happy with the result. By the time it's done, the completed lyric and melody will almost certainly vary massively from the original input.
After that, you just have to note the tempo and arrange accompaniment and you have an actual song.
A good lyric is a thing which will stand rephrasing and reinterpretation and a variety of voices and styles. A poor lyric is usually self-evident and often by Wayne Hussey.
Endnote: Lyrics can be a source of misunderstandings and misapprehension by those close to the lyricist, just as can any other form of creative endeavour. If a woman writes lyrics along the sentiment of "I hate you and wish you were dead", it's probably wise for her husband not to read too much into that without additional evidence.