1) Every piece of writing advice you will ever read, no matter who wrote it, is wrong.
Oh, it may not be wrong for you. But it’s wrong for someone. There’s not a path, a rule, a method, or a technique out there that’s universally applicable. If you follow anyone’s writing advice slavishly, you’re not going to succeed.
2) You’re not special. You have to work to become a good writer. Maybe a little, maybe a lot; natural talent enters into it, certainly. But you’re not going to start off at a professional level. You’re just not.
3) You will be wrong. Sometimes suggestions and revisions and so-called "mistakes" are purely matters of taste. Sometimes they’re not, and the suggestion is flat-out incorrect. But sometimes, the problem is yours. An editor or a fan or a reader or a friend will point out a problem with your book that actually has merit, and no matter how much you argue, or love the way you wrote it, it will still have merit. Your book is not perfect as you envisioned it.
4) You need an editor. Always. Whoever you are. No matter how precise or attentive you are. No matter how long you give yourself between writing and rewriting. You will always, always, always miss things that a new pair of eyes would spot.
5) Publishing a book, even e-publishing one, isn’t free. If you’re publishing traditionally, the publisher pays those costs. If you’re self-publishing, you’re going to have to. But they must be paid. You must have editors, both content and copy. You must have a halfway decent cover. You must have non-eye-bleeding layout and formatting.
If you can’t afford to acquire an editor and the other necessary professionals, you cannot afford to self-publish, no matter how long you’ve been working on your book or how good you’re certain it is. Save. Work extra. Do what you must, until you can afford to do it right. Or don’t do it.
6) Every rule has exceptions. Including, but not limited to, these. You will always be able to find an outlier. Someone who produced a fantastic book without an editor. Someone who made a zillion dollars on their first book. Someone did work for "exposure" that actually got exposure. These are all serious long-shots, but they do happen.
These exceptions don’t make the rules invalid. They’re still rules. They’re still necessary. They’re still true 99.99999999repeating % of the time. Choosing not to follow them because exceptions exist is like choosing not to look before running across the freeway. It’s possible you’ll make it, but the odds are not in your favor.
There are exceptions. You are not going to be one of them. Suck it up and work.