Reasons to join a writing critique group:
1) It motivates you to write.
2) It encourages you to revise.
3) It teaches you to read critically.
4) It trains you to give - and receive - constructive criticism.
5) It helps you hone your craft. It really, really does.

But all writing groups are not created equal. Look for a group that meets most (or all) of these criteria:
1) The group is small. 5 or 6 writers is ideal. 7 or 8 is do-able. 9 or 10 is pushing it. Anything larger than 10 means there won't be enough time to discuss everyone's work at every meeting. The goal is to assemble a dedicated group of writers who will read each others' work regularly enough to become invested in it.

2) The group is reliable. Look for other writers who are willing and able to meet consistently. I find that every week is too intense for me, but less than twice a month is too infrequent. Every other week is ideal. But that's just me. Find a group with a schedule that works for you.

3) The group is friendly. This might sound silly, but sharing your work can be scary. Find a group of people who give criticism without being cruel. Avoid groups where one or two people dominate the discussion. Above all, find people with whom you "click." If you hate your writing group, it's not the right group for you.

4) The group shares similar goals. If you're a poet, join a poetry group. If you're a romance writer, join a romance writing group. If you want to get published, find a group of other writers who are trying to get published, too. If you join a group of people who don't read the genre you write, it may be difficult to get - and give - good feedback.

5) The group members are at similar levels. It's tempting to seek out the most experienced writers you can find, but if you're new to the writing game, you're likely to find yourself intimidated by such a group. Similarly, if you're already revising your novel, you might not get much out of meeting with less seasoned writers.

So now you know what you're looking for. Where can you find it?

First and foremost, a writing critique group is not the same as a creative writing class. If you're looking for a teacher, homework assignments, and/or writing prompts, sign up for a class at your local community college or arts center. A lot of writing critique groups develop when students opt to continue writing with each other after a creative writing class has ended. But the writing class itself generally functions very differently from a writing critique group.

Writers' conferences are a great place to form writing groups. The people you meet at conferences are generally committed to writing, and the immersive nature of a conference gives you a chance to get to know each other.

The best place to find writing groups is probably Search the listings in your area. And if there isn't a group, organize one yourself. I did that five years ago, and it was one of the best things I ever did.

Write on!