I agree with professional editing. Many people believe they write well and simply don't. I don't like writing but I love the finished project after ten or twelve drafts. Other people can pick up typos and technical things that you can't see. What I did at teh law firm was to read samples of associates' writing to see which ones I loved. I made a list and read their work on a regular basis. They all attended private school.
If you live near a city there may be community courses. I knew many writers in college. There used to be a thick book sold at subway newsstands called the Writers' Digest. They swore by it.
Madeleine L'Engle told me the problems she faced finding a publisher for A Wrinkle in Time. Every publisher rejected it. She stood her ground. I would cave. Finally, Farrer, Strauss, Giroux expressed interest but they could not figure how to market it. The book appears to be young adult on first glance but the lessons are universal. C.S. Lewis' Narnia Chronicles inspired her. She said to market it to everyone. Madeleine became famous, weatlhy, and traveled the world with a State Department program. She volunteered in church work and charged writers money for workshops.
It may be crazy but I still believe it can happen to us. Not caving would be the lesson for me.