Let me get this off my chest first: I cannot spell. I have been known to spell the same word three different ways on one page. Worse: I cannot proofread.
I once earned my living as a tech writer, and a good one. I got reviews that to prove it. They boiled down to “This woman walks on water, if only she could proofread.” Under attention to detail it would be ding ding ding. How bad was it? I once let the graphics department paste up an entire chapter’s header with a misspelled word in it. Remember folks, that was in the day when such tasks were done manually and were labor intensive. My supervisor was not pleased. What I got out of that was a confidence that I could write and sure knowledge that a writer and and editor and a proofreader are three different things and I was only one of them. Spell checkers help, except when they don’t. Some checkers just embarrass me with inappropriate substitutions.
Now that I work with an editor (and let me say I love my editor) other bad habits have come to light. I’ve come to believe that spoken English may be my native tongue, but written English is a foreign language. She = finally taught me how to use dashes and ellipses appropriately, how to format thoughts vs. dialog, and greatly improved my sentence structure. She also tries to make me avoid crutch and filter words. The number of times I used “look” in my last manuscript was exceeded only by the number of alternative words for the same concept in the thesaurus.
She is a patient woman! Luckily, she likes what I write.