I began answering before I thought of having a more formal review of the suggestions made by others in the original thread.
Further down may be Posts that are more specific to those responses.

"Where can I learn about proper lyric/song structure?"

Your local librarian has or can get any book you'd like to read.

Your own music collection of Songs you think do Structure right can enable you to study what you think is 'right' about those Songs.
Conversely, you can study what you think Songs do wrong in Structure.
Pick one Song. Write out the Lyric. Can you discern where the Verses begin and end, whether they have internal components that affect how the Song 'works' or doesn't?
How long is the Introductory Movement? That's the first sounds you hear, that 'Hook' your interest, until the Verse or Chorus begins.
Pick another Song, or several more, to repeat that analysis of what you think they do right, or wrong.

Some Songs begin with the Chorus.
The 'Intro' is whatever sounds first command your attention.
An Introductory Movement need only be long 'Enough' to serve that function. It can be long, if it is interesting 'Enough' on its own. But it can be 'Too Long', 'Too Much' or 'Not Enough' in the concept of 'Enough'. A Song, overall, can be Too Short, Too Long, Enough, Not Enough, Too Much.

How much is 'Enough', versus how much is 'Too Much' or 'Not Enough'?
These are judgment calls you, the first listener, as the Song-Writer, can make.
Listeners will make their own judgment calls.
If your Intro isn't effective in Hooking and sustaining their interest, they drift off to their own thoughts. You may get them back when the next Structural component begins, Verse or Chorus.
The same thing happens at that point. Either you Hook their interest, and sustain it, or you lose them again because what you do in that component is 'Not Enough' or 'Too Much'.
'Enough' should not be an elusive judgment. In time that judgment call should come to you naturally. You sense when Repetition is 'Enough', when the Exposition has supplied 'Enough' detail, when it is 'time' for Change, to get to the point in the Chorus, time for THE Hook.

Timing is of strategic importance. How long can you expect them to sit and attentively listen to whatever you're doing in an Introductory Movement or a Verse or a Chorus, or a whole Song? Is your expectation reasonable? Is it logical that what your composition is sending to their ears should have that sustaining effect? Or is it logical that they will drift off to their own thoughts? What 'Hook Factor' can you assess the sounds you're making, the words you're 'saying', to have on the listener?
There are limits to the Human attention span.

You, playing, singing, may be more entertained than others will be. It's fun to play, to sing, to emote, to enjoy the Prosody of how the Lyric works with the tempo, the beat. You may not even think of making a judgment call about whether it will also be entertaining to the listeners. Sometimes you miss your cue on when to start singing, so you run through the Intro again, making it twice as long. Will they stay attentive? In live play you do what you have to do, come up to that cue point again and hopefully get it right the second time. In a recording, you have to get it right. 'Enough' Intro, and begin the next Structural component, whether it's a Verse or The Chorus.
Instrumental compositions can benefit from the same judgement call of Enough, long 'Enough' to have entertained, and now it is 'time' to Change, time to Repeat.

What you Register for Copyright is a Lyric, and the Melody to which the words are sung.
Form SR, Sound Recording, can Register an actual recording of a performance, the Arrangement, instrumental accompaniment, the Lyric and the Melody to which the words are sung.

The function to be served in a Verse is 'Exposition'. The Singer, or the Singer-Character, whose persona the Singer 'assumes' to deliver the story in the Lyric, is telling details of a situation, setting the scene, putting props on a stage where the Singer-Character can 'exist'. The intent is to get the listener to 'suspend disbelief' and 'believe' that it is a reality, a story that credibly could have happened to the Singer.
The Singer-Character may be speaking to the audience, telling them the story.
The Singer-Character may be speaking to a Love-Interest Character, or other Character in the story, letting the story unfold for the listeners through that eves-dropped 'conversation'.
The 'Enough' concept applies.
How much Exposition is 'Enough' to Hook the listener? How much is 'Too Much', losing them again? How much is 'Not Enough'?

When 'Enough' Exposition of the story is told to the listener, in Verse I, it may be 'time' to get to the Chorus, the gist of the story, the main idea, THE Hook. That main idea is likely the title of the Song, some few words, a phrase that sums up the Exposition so far, a phrase the listener comprehends as having that meaningful concept. It is THE Hook as opposed to other Lines or phrases that have Hook Factor.

Verse II does more Exposition, tells more of the story, leading logically to Repeat the Chorus. Repetition and Change. Enough Repetition to supply Structure. Enough Change to keep it interesting.

A Chorus can be several Lines, a Stanza-Type Chorus.
A Chorus can be a single Line, a 'Refrain' of Melody and Lyric, the main idea of the Lyric, a Refrain-Type Chorus.
Folk Songs often employ the Refrain-Type Chorus, a single Line ending each Verse.

The concept of a Pre-Chorus, sometimes called a Pre-Chorus 'lift', is often misconstrued as a Stanza of several Lines separate from the Verse. It can simply be the last Line or two of the Verse, 'lifting' Melodically or dramatically to lead into the Chorus. Simplify. Keep It Simple Stupid! I mean, Keep It Simple Sweetheart! Sorry baby!

A Verse III can finalize the story, a 'denouement', an end.
A beginning of the story in Verse I, a middle in Verse II, and an end in Verse III.

The Third Verse Curse is a writer's dilemma when they can't think of a satisfactory end to the story.

Despairing of finding it, writers often resort to a Bridge, a device to break the Repetition with Change, Lyrically pivotal information, coherent in the Storyline, with its own Melody, different from the Verse or the Chorus, enabling a third Repeat of the Chorus to end. A Bridge may be a brief instrumental component.

The judgment call of 'Enough' applies in how much Repetition is necessary to supply Structure, and how much Change is needed to keep it interesting, to keep the listener Hooked. You're the Song-Writer. You're the first listener. Your judgment will be seconded by other listeners.

The final Musical Movement is called a Coda.
'Intro' is slang for 'Introductory Movement'.
'Outro' is a logical abbreviation for 'Outroductory Movement' but 'Outroductory is not a word.
The Coda, often called a 'tag', is simply the final Structural component of the composition. It is likely a series of Repetitions of the title, THE Hook, the main idea. It may be an instrumental composition.

Structure within a Verse or Chorus can vary.
A common four-Line Verse, Rhyming Line 2 and 4, or 1 and 3 AND 2 and 4, or 1 and 2, 3 and 4, can work.
Nursery Rhymes offer an alternative, Rhyming Lines 1 and 2, and leaving Line 3 un-Rhymed, then having another Verse or 'Stanza' Rhyming Lines 4 and 5, and Rhyming Line 6 with Line 3. Any variation you can make work is fine.
Rhyme in Nursery Rhymes is designed to make them memorable for children with limited vocabulary.
A Song Lyric employs Rhyme for the same reason; to enable the listener to 'remember' the words, to 'get' the story you're trying to tell them.

Internal Rhyme can be interesting.
Again, the 'Enough', 'Not Enough', 'Too Much' judgment call is considered.
While a tongue-twister can be fun, is it still fun in a Song?

Last edited by Gary E. Andrews; 10/19/22 02:43 AM.
There will always be another song to be written. Someone will write it. Why not you? www.garyeandrews.com