I learned most of the craft of fiction in my writing group. I’ve been in the same one for almost 18 years. During that time almost every member of the group has been published.
But it takes some serious thought. It’s NOT a social group. We meet once a week and we read out loud. Then the other members comment on what’s been read.
First rule of commenting: Talk about what “stopped” you. What took you out of the story. Even if you’re not quite sure why it stopped you, someone in the group might know.
Second rule: When it’s your turn to comment, don’t repeat what someone already said. Just say, “I agree with Joe on that point.”
If it’s your work that’s being critiqued, try not to be defensive. You’re not there to defend your work. You’re there to improve it. And if more than one person has the same comment, you should consider revising accordingly.
There are times, of course, where you just don’t want to change something. Very rarely, in my case. But, if and when it does happen, simply say, “I’ll take it under advisement.” I’ll bet you ultimately will change it.
Getting the right people in a group is the hardest part. It helps if everyone is writing the same genre.