Online grammar check services can be useful, but they won't teach you one important fact: Rules are meant to be broken. That's not to say that breaking grammar rules is imperative to writing well. It's not. But taking chances can distinguish a great writer from a good writer.
One thing to remember: Clarity trumps all rules. If your meaning is clear no matter the rules you've broken you've achieved your purpose, which is to communicate information, thoughts or feelings through the written word. However, one foundational fact precedes that premise: You have to learn the rules before you can break them.
Writing is a discipline. It's an organization of thought. To organize your thoughts effectively and efficiently with clarity you need to be disciplined enough to master all the rules.
Rebellious, undisciplined rule breakers may appear witty, clever and even popular, but to truly master the craft, you first must master grammar. You must master yourself and hone your skills through obedience to stringent guidelines.
Some may think this stifles creativity. Nope. It bolsters it. "Prose is architecture, not interior decoration," Ernest Hemingway said. After you learn to effectively apply the rules, to write with order and compose with precision, then you're ready to go ahead and break the rules.
Feel free to split infinitives, to boldly splice a verb where no verb has been spliced before. And don't be afraid to start a sentence with a conjunction or end a sentence with a preposition. Get your grammar groove on. (A little alliteration helps too.)
It's fine to use slang and contractions. Your readers will be blown away and think you're a whiz. You may even find a need for a double negative. Never a day goes by that I don't miss my grammar check. Not bad, not bad at all!
Don't shy away from fragments as long as you follow the clarity rule. Clarity above all.
And one-sentence paragraphs are acceptable too.
So are one-word sentences. Indeed. Yep. Huh? Cool! Wow! Perfect! And feel free to use any punctuation that works, even if it means a string of exclamation points.
Let's not forget two important aspects of good writing: spell check and online spell check. Those are both effective tools because no one knows how to spell every word. But spell check does. Nevertheless, there's a manipulative purpose to this paragraph. It's for search engine optimization, or SEO. Web writers put keywords into their content to ensure it's read and properly categorized by Google bots that crawl the web. That helps the content rank high in Google search results, which brings readers to the writers' websites. If you're reading this, you may have searched for "spell check" or "online spell check." Those are SEO keywords I inserted into this paragraph. There's no rule that says I can't use words to lure online readers, but if there is, I just broke it.