Every writer has his own style, of course. Faulkner didn't write like Hemingway, who in turn didn't write like Lovecraft, who in turn didn't write like Charlotte Bronte. But every writer - if he is a writer, and not a pretender - knows how to write properly.
There are books out there - with famous names on the cover, and famous imprints on the spine - which contain clear evidence that neither the author nor his editor know how to handle the English language. I'm not talking about such idiosyncrasies as odd notions of where to use semicolons, but actual incorrect English.
For instance, there's the incomplete sentence. If there's one thing English teachers inveighed against when I was in school, it was sentence fragments. But today they're all over the place, and I can't figure out how anyone can ever write or read one without instinctively wanting to fix it, by connecting it to the rest of the sentence.
In addition to problems with correct English (and no, I'm not going to multiply examples ad infinitum ad nauseum - that's not my purpose here) there is the loss of vocabulary. This is very apparent in the media, which seem to know only one word for something that has broken. During the BP oil rig leak (it's not a spill unless the material is in a container and spills, which didn't happen in this case; herein is another example of my point) I never heard a single talking head on TV speak of a burst pipe, nor a broken one, but always of a "busted" pipe. Surely someone somewhere in the vast conglomerations that constitute American media empires could have dug out a thesaurus, and provided a list of synonyms, but clearly no one did so. Nor did anyone catch the fact that "busted" is a colloquialism, a casual usage, which is incorrect English and not appropriate for people who purport to be purveyors of reality to their viewers.
I hope that no one who posts his work here on Fine Stories is incapable of using English correctly. A "writer" who can't use English is fundamentally not one whit different from a "carpenter" who doesn't know how to use a level or drive a nail - he's a fraud. If you don't know how to use English, then you're not a writer. You may do something with words, but it isn't writing - just as a "carpenter" who doesn't know how to use his tools might manage to accomplish something, but the result isn't carpentry. I devoutly hope that everyone who here presents himself as a writer is competent in the use of the language, for that is the sole tool a writer possesses.
Years ago, when the Worldwide Web wasn't even 10 years old and when people spoke of the Internet they meant ftp, gopher, and e-mail, I encountered in cyberspace someone who claimed to be a writer. On one occasion he said something to me - I have no idea what, now - and I replied to it. He sent me back an angry message, castigating me for responding to what he hadn't meant. It turned out that what he had intended to say was the exact opposite of what he had typed. That person might have been any number of things, but he was no writer; no one can legitimately claim to be a writer who is so unable to use his mother tongue that he says exactly contrary to what he wants to say.
Because of my computer situation (which I won't go into here) I'm able to post my stuff, generally on a weekly basis, but it's just not feasible for me to read others' writing (I am trying to figure out how to overcome the disability, but haven't yet conjured up a workable plan). I hope that what I'm missing is good writing, rather than poor writing. I would hate to think that people are posting here in English who just don't know how to speak English.
Of course no writer is perfect. I certainly am far from perfection. I catch errors every time I go through something I've written, even if I've already proofread it a dozen times. But we can improve.
And aside from the hackneyed advice about how to improve (practice, practice, practice), there is an invaluable aid to writer well. One must read. Someone who never reads, will never be able to write - at least not well. No matter how many classes someone takes in creative writing (I am afraid that there is such a thing as writing which isn't creative - it infests Madison Avenue; the writing in the average ad is abysmally awful), if he never reads anything, he'll never be able to write anything that's worth his trouble. And he certainly won't ever write anything that's worth the trouble of trying to read.
Therefore, read. I could name author after author, but tastes differ, and what I enjoy others might find tedious, irritating, or incomprehensible. I shall, therefore, only recommend one name, because of all the authors I've ever read he had the most comprehensive command of the English language. I speak of William F. Buckley, Jr.
Now it may be that I'm the only one who's ever been to this site or ever will come here who agrees with Buckley's politics. That's all right - you needn't even read his political stuff to learn from him (though you can certainly learn from what he wrote on politics). Read his books on sailing. Read his books on his daily life. Read his novels (they're not as good as the sailing or mini-biography volumes, but still...). Read his English. Pass over, if you wish, his occasional Latin or French phrases (that's what I do, since I don't speak French or Latin, and would rather be mute than learn French). Examine how Buckley used English. Note not merely the $64 words, of which he had an abundance, but the ordinary words, and the way he used them. Don't emulate him, necessarily (I especially urge you not to emulate his use of the passive voice - that's the most flabby, pretentious aspect of the English language), but learn from him. There are right and wrong ways to put words together into sentences, just as there are right and wrong ways to put together an internal combustion engine, and if there's anything you can learn from Buckley, it's the right way to do it.