To be honest, I think you probably are overthinking it. I'm not sure what rules you were taught apart from trying to avoid split infinitives, not ending sentences with prepositions, and not using "like" to mean "such as" (is that what you meant?), but most of the rules are fairly easy. The ones that you find you actually care about will soon become second nature to you, and you'll no more have to think about what they are than you have to think about what sound is made the letter "b" - something you must have been taught at some point (right?), but which is now totally transparent to you.
Some of these rules, such as the one against split infinitives, are actually quite dubious, but I think it's worth being aware of them anyway. Often, grammar or no grammar, a construction with a split infinitive is the easy and lazy way out for a writer: some other construction will often sound smoother and more effective. For example, a lot of people write "try to not" - as in "Try to not annoy him!" - when it is probably more natural and logical, and less clumsy, to write, "Try not to annoy him!"
So, I do think it's worth learning these rules, but treat them as tools. You don't need to swear never to split an infinitive, or never end a sentence with a preposition, again. You'll find cases where the "ungrammatical" construction is best. It becomes a matter of judgment. Part of developing skill as a professional writer is developing that judgment, and you probably have a lot of it already.
As for the role of publishers (copyeditors, editors, etc.) ... well, it really does fall on you in the first instance to develop a clear, undistracting, attractive style. Copyeditors and the like can be useful, and they are likely to correct any clear-cut grammatical mistakes, but it's not their primary responsibility to worry about style. Presenting work in a style that will impress commissioning editors, and such people, really is a skill that we all need to work at. (Notice that the previous sentence ends in a preposition! And it's none the worse for that - nor is this one for starting with a conjunction.)
The other thing is that professional-level writing usually involves many, many drafts before you submit it. You don't need to get everything right first time if you're feeling inspired and writing at white heat. You'll have plenty of opportunity to tinker with it later.
I can offer you my take on things, though I'm about as typical as the proverbial hole in the equally proverbial head.
Most of what formal learning I have about writing, I got from grammar and high school. Keep in mind, though, this is 45 years ago, when all the parts of speech were probably taught before ninth grade and knowing how to diagram sentences was de rigeur. Majoring in engineering in college, I was required to take only one semester of English, so I can't say that that particular element of my education had much influence on my writing style.
The rest of college had a considerable influence, if indirectly. Obviously, I had to read a lot of technically oriented books. calculus, physics, electronics, dynamic systems were all an automatic part of the menu, and with that reading came a very thorough indoctrination in the style of technical writing. The more literary end of the spectrum came from a senior-year course in Utopias, where I got a taste of Kurt Vonnegut's Player Piano and Robert Heinlein's The Moon is a Harsh Mistress, among others.
After college, my writing style got pokes and prods from all over the place. Reading Heinlein and Vonnegut had put a real bee in my bonnet for both of them, Heinlein particularly. Later a friend's gift of C. S. Lewis's The Lion, the Witch, and the Wardrobe added to that and intrigued me to the point of attempting my own take-off on the Chronicles of Narnia in novella form.
It was much later when I joined a small instrumentation company that my technical writing skills were pressed into service. I was a field service engineer in a company that had next to nothing documented, other than obtuse engineering and hardware manuals which offered nothing to those tasked with servicing this equipment. I found myself driven to formalize what is now referred to as "tribal knowledge" about the procedures and techniques and tricks of the maintenance trade, culminating in a fully blown maintenance manual for that outfit's primary product. I drew my style from Resnick and Halliday and Lees and Hendrickson among others, mimicking the word flow I remembered from them. I must have been pretty successful, as I ultimately wrote no less than six such manuals for them over a quarter-century.
Through all of this, I have never so much as picked up a copy of The Elements of Style, and I'm not sure I've needed it that much. As I stated earlier, I'm something of a mimic. If I have a technical writing style, it's bent toward being tight and practical, mostly because that's what I want to see when I'm trying to learn something new, especially under time pressure in a service situation. My fiction style probably favors Heinlein, as he is my favorite author (and to be honest, I'm NOT all that well-read!), though it is also tweaked by the rest of my life experiences.
To your point (FINALLY!) - I haven't had a lot of editing help, and maybe it shows and maybe it doesn't. I've been known to take an axe to infinitives here and there and leave the occasional preposition out to dry, with only a period following. The question becomes: how tight or formal do you want to be with your prose? The rules you mention are hardly hard and fast, or you wouldn't see dangling prepositions or split infinitives at all in any modern writing. I treat them as guidelines, not as absolutes, and I seem to have done okay, at least.
Your mileage may vary.
Loren, I am impressed! However you got your influences, your sense of humor comes through ... in short, precise sentences, with sharp focus. Thanks for sharing.
Grazie, Joan! Still, it doesn't hurt when you're running Firefox with built-in spell-check! I still get it wrong here and there and Firefox is quite good about letting me know!
Grammatical errors are my nightmare. I have spell check to gets me over that hump, but grammar gets to me. I've read so much technical writing, I have trouble loosening up to get a flow going. I respect anyone who can tell a good story with some kind of point to it. I had a student when I taught at a boys' ranch, a black kid who was in a rage at the world. Every other word was a disgusting one. He started writing his story, which was steaming with obscenities but this kid had a story to tell. I took him to a local college English professor and he, too, thought this kid had talent. His story was raw, obscene, violent, but a boy with heart and dreams and goals, and hopes came through. Sadly, he was shot and killed robbing a grocery store.
Two novels I have completed. Well, sort of. In the process of looking for a publisher, I have found that each publisher is different. If you want to write, the best thing you can do is find an editor. Some of us are driven towards the more creative aspect of writing, while others are far more technical. Many a grammer nazi I have encountered. Vast is thier knowlege of grammer, but piss poor is thier ability to follow story arcs, Character cultivation and development.As someone who has long struggled with Dyslexia a good editor who is aware of this issue is important. If they expect your drafts to be perfect their asking to much. Secondarly, anyone who has written more than 100,000 words can tell you, that you become "error blind". You can have a hard time editing your own work simply for the fact that you wrote it, therefore "Already know it" and miss a great deal that a fresh set of eyes can find.