I belong to a writers club, 23 book authors and me. They read their chapters and I read my Medium articles aloud to each other at weekly meetings. Then everybody offers their critiques. It is a humbling experience.
Besides the normal content and grammar, I look at their chapters as if I was reading them on my Kindle. Most common problem: very long paragraphs.
By the way, I read every comment and add something only if I have something significant.