YOU, The First Listener.
Humans have been writing Songs for millennia. They have not exhausted the possibilities. Someone keeps popping up out of the woodwork with a new Song. And occasionally they write a good one. There's a lot of mediocre product that gets put on the market, less because it is remarkably fresh and entertaining than because, if the industry doesn't find someone to sell, they're out of business.
Opinions? Obviously several people had opinions about that product they participated in getting to market. Some probably felt it was better than nothing. At least we've got something to put out there, to promote the live shows where we make money. Some people buy the recorded product and attend the live shows, not because they are 'wow'ed' by the Song(s) than because it's something to do. More than once someone has shown up at the house with the 'new' music by the 'new' artist. They're enthused. Their criteria for what is in the product to be enthused about is different from mine. They had often spent their money on a pig in a poke (That's a pig, or something, moving in a sack, that you have not actually seen, for which you lay down your money in exchange to own.) They heard that one Song, and bought the other 13 on speculation that they'll like them too. I've done it. And been disappointed in the other 13. I once paid $17.00 for a CD to be supportive of an act. I want my money back. I considered investing in the debut CD's of two acts, literally financing at a couple thousand dollars, without having heard their product. I'd seen their live shows and they were talented. But their creative product, which I luckily heard before I stuck my tongue on the anvil and invited them to hit it, was not, in MY opinion, worthy of their investment, let alone mine.
Opinion is really all YOU have to make a judgment on your own product, and that of others. You can be wrong about yours and wrong about theirs. Or you can be right. When you do your Market Research, demonstrating the Song(s) and getting feedback from 'consumers', listeners, consuming with their ears, and perhaps 'consumers', laying down what someone called "The coin of the realm" in exchange for the pleasure of owning your Song(s) for repeat listening, then you might be able to confirm, or deny, your own opinion, your Momma's opinion, that girl in the front row who seems like she can't get enough of you, that crowd with the 'polite' applause versus that crowd that applauds with a perceptively genuine enthusiasm.
All you can do is put your product out there, on the table, and let the consumers decide. Their opinion is the only one that matters. Some professional critics gained a reputation for being wrong. If they said it was bad people learned to go see for themselves, because it was usually good, and that critic was just trying to downplay the competition for acts he had a vested interest in promoting. His 'credentials' got him to the 'microphone', on the pages of the 'magazine', but his 'opinion' lacked trustworthy credibility. If you're selling your product, recorded, live play, and making money, odds are you've done something right. If your Market Research shows you're not selling, recorded, or live, you might want to invest yourself more diligently in the day job (The boss is watching!) and keep refining your product.
Of product; there is inspiration, those words, that guitar work or piano work that you stumbled on, that tumbled into your brain and out of your mouth, or maybe out of your mouth, bypassing your brain, and YOU, the First Listener, said, "Hey! That's...that's interesting. That's...that's GOOD!" Your judgment at that point is all that matters. You got enough, inspired with something you didn't plan, something that just 'happened'.
Then, there's 'Craft', the rewriting, the incubation of the idea, YOU, the Songwriter, cogitating on just who this Singer-Character is who imposed themselves into your brain, caught your attention, Hooked you into 'assuming their persona', the way you think it might Hook others.
Now you start to 'Suspend Disbelief' yourself, to conceive the Singer-Character's world, his situation, what the ideas behind what you've got so far implies about a 'Storyline', a tale to tell. Not necessarily 'Your' tale. 'His' tale, this mysterious stranger. You try Lines and words and you 'Edit', you, the First Listener, make judgment calls about what works Rhythmically, ideologically coherent in that story, or, just Rhymes. You set traps, or stumble into them, like you said 'heart' and now you're stuck with 'apart, art, bart, cart, dart, Don't say it!, mart, part, quart (Near Rhyme? Imperfect Rhyme? Soft Rhyme?), start, tart, wart.
You Grab-A-Rhyme, 'deep inside', 'driving me insane', 'what can I say'.
YOU, the First Listener, employing your 'credentials', your qualifications to make these judgments, YOU go back and rewrite the Lyric.
You decide whether the pitch of Melody drops off, perhaps in volume too, at the end of the Line, or if you chew those vital Rhyme-Words off your tongue like Dylan, so they get 'sent' in a way the consumer can 'receive', delivering them the meaning of the whole Line. For want of a word, a Line is lost. For want of a Line a Verse fails. For want of a Line lost in a Verse the Chorus fails. Piss on your Bridge! It ain't workin' either! LOL
You are the First Listener. Without employing your 'credentials' to make all these judgment calls there would be nothing for the rest of the world to critique, the consumer judging whether to spend their hard-earned coin, the critique with prejudices and preferences of his own. Don't 'write country'. Don't 'write Rock n' Roll'. Don't 'write easy-listening or jazz or hip hop or world beat or opera'. Write...Songs. Write Songs you, the First Listener enjoy singing, but that Hook you in a way you think should Hook the next listener, and the next. Your credentials are as good as anybody's in the creation phase. Other people's credentials only come into play when you take your product to Market. By then you should have a little polish on it, should have made some judgment calls, and should find it appeals to the others like it does to you.
Despite 1,000's of years of Songwriting humans have not exhausted the possibilities. There will always be another Song to be written. Someone will write it. Why not you? www.garyeandrews.com
Beside writing a song for yourself, for your own pleasure,
you should not write for other songwriters,
you should write for the listeners and hoping they will appreciate it.
K.I.S.S. Keep It Simple and Singable