I have a BA in English and Masters in Communications, but I spend my work hours writing and evaluating business contracts, looking at spreadsheets of numbers, and managing budgets for a magazine. If you like to write, consider marketing or communications degrees. PR is an option too.
"Nitty, Gritty" is what editors want in a manuscript. If your grammar is awkward, editors will most likely reject your manuscript because they don't have time to rewrite it. The writers of classic books are still famous for their use of the English language. Read those books.
Start a blog and write everyday. (Who knows? You might even earn some money from it.)