The course from the Minimalists is literally just a piggyback segway from their Netflix documentary. They are capitalizing on the only two things they really know how to publicly do (write and get rid of shit), and they're running out of things to write about getting rid of shit. Don't waste your time or money.
I second both
@blogzandstuff and
@Asif WILSON Khan's suggestions. I use Grammarly and Hemingway as pass-throughs for all my content writing orders and personal website processes. Grammarly does a great job at suggesting alternative words that I may miss out on, and Hemingway is stellar at ensuring that my content does not get too wordy or run-on like.
Other than that, just write and write and write more. Learn by doing.