I decided to make a few entries here on the pathway to self-publishing. The second step is get a critique group, some people who will read your stuff and make constructive comments.
The first step is to write. This can never be said enough. Robert Heinlein (Rule 1), Stephen King (2000 words a day), Jim Butcher, and others tell you the obvious. To be a writer you have to write. If you don't write, you got nothing. So, write!
Once you have pages written, then somebody else has to read them, and make constructive remarks. Who should be in your critique group? Somebody who can give constructive remarks. I'll elaborate on those later, but your critiquers must be willing to take you to task. They cannot just say, "Oh, it's nice," or similar vague remarks. They have say what's wrong. Plot, pacing, conflict, characters, setting, background, grammar, details, everything has to go under scrutiny. If you aren't annoyed at your group occasionally, they aren't being direct enough. Don't lose your temper or quit though. They are trying to help you. As a writer, you'll have to be thick-skinned.
Another quality they must have is familiarity with your genre. If you're writing hip, grim, cutting edge modern day fiction, and you find a bunch of older women who like cozy genre romances, they won't be able to help you much- aside from telling you they don't like the main character. Your critiquers will have know what tropes you are working with, where you are heading with your novel and sort of what to expect.
What are constructive remarks? They are helpful, exact and directed at the writing. They examine the plot - is it believable, are there holes? Pacing - is it too slow, or need to slow down a bit? Characters - likable, unlikable, too perfect, too whiny, consistent. Setting - is it believable, consistent. If set in a hospital, does it feel like a hospital? Do the background characters act like nurses, residents, and clinicians? Same for other settings such as military or the criminal justice system. You should get comments about grammar, repeated words, and inconsistent details eg "hero's car is a blue Ford at beginning of chapter, and red Dodge at the end."
As best they can they do not go after politics. They may say things like "this isn't how a homeless person acts," but not "how dare you make fun of the downtrodden, you scummy rich asshole!" Again, that last comment would break the rule to address the writing, not the person.
Finally, what does it mean to have people read your work? One method is to gather together and read ten pages out loud, with your group annotating copies as you read. You won't like it, and it'll be embarassing, but you'll learn so much. Repeated words jump out of the page, as do extra dialog tags. Vague phrasing will get caught, and you'll get suggestions on how to improve it.
Eventually, you'll need to branch out, to having the group read an entire novel and meet to discuss it. You can't get through a novel very fast at ten pages per meeting, and you'll stop making those mistakes. You'll want the input over the whole work, and you'll want it quickly.
Read your work, make constructive remarks. That's what your looking for in a critique group.