A critique group can help you refine your writing and get your manuscript ready for publication. The support and ideas are invaluable. But it does take some courage to put your writing out there for comments and criticism. You also need to be in the mindset to take the criticism and improve your manuscript.
Find a group that fits your work style and genre. Some are virtual (online), and others are in person. Mine meets monthly at a local library. We have six to nine authors who attend regularly. It may help if you can ask to visit before you join or submit your work to get an understanding of the rules, conventions, and group dynamics.
Make sure you know the rules. In our group, there has to be at least two submissions in order to have the monthly meeting. We also don't require members to submit something each month.
We make notes about grammatical and formatting issues and give them to the owner. We don't spend the group's discussion time talking about commas. Also, if someone mentions an issue that others noted, they jump in when it is first discussed, so we don't have to repeat items that have already been mentioned.
I like that my group has a good mix of published and pre-published writers. There is also a good balance between readers and writers. Our group started out with all female members, but we're now more gender and age diverse. That's helpful because we get a variety of opinions and ideas.
Don't take the criticism personally. The goal is to offer help to improve your writing. You're there to listen and learn, not to defend your work against every comment. And in the end, they are all opinions. If you really don't agree with something, don't use it.
I am very fortunate that my group focuses on mysteries and crime stories. The critiques are more valuable when the group members know the conventions of the genre. They also offer connections and advice that help writers at all stages of their careers.
You need to make sure that you're contributing to the group. Make the time to do serious critiques/reviews of their submissions. It takes some effort, but the advice has been invaluable for me.
My group is supportive. We help each other with marketing, social media, book launches, and technology. And we celebrate each other's successes!