I often keep revising until a text-to-speech program is able to read my writing in a way that sounds natural. Following that approach led to great results in university writing courses and, recently, got me through the process of writing and officiating a wedding.
I share this because many of the comments respond to the "write like you speak" advice with statements similar to "I don't speak well, so 'write like you talk' won't work for me". We spend every day of our lives consuming spoken language and reading written language to ourselves and, as a result, we are able to recognize speech that sounds clear and well spoken. Even if you struggle to speak improvisationally, listening to what you've written can help to evaluate the understandability and flow of your writing.
I share this because many of the comments respond to the "write like you speak" advice with statements similar to "I don't speak well, so 'write like you talk' won't work for me". We spend every day of our lives consuming spoken language and reading written language to ourselves and, as a result, we are able to recognize speech that sounds clear and well spoken. Even if you struggle to speak improvisationally, listening to what you've written can help to evaluate the understandability and flow of your writing.