I'm pretty sure I've mentioned the importance of a writer's group. Even though they can be a little intimidating at first, they're just so useful, helpful, and...well, supportive. Of course, you have to find the right group for you. I've been in several groups and liked different parts of each. For me, I find that personality comes into play. I like when there are writers of varying levels...some are first-time, some are seasoned. I like when I fit into the middle somewhere; that way, I'll get good advice and can offer advice, too.
Currently, I'm in two groups: one that meets once a month and has over 20 writers of all genres (poetry, short non-fiction, short fiction, long fiction); and one that meets every two weeks and we all write creative long works.
I'll tell you how the 2nd group works (because different groups have varying ways to critique):
Every other Monday (like today), my group meets. We bring excerpts of our novel (or non-fiction book), limited to 10 pages, and read the excerpts aloud to the other members. I love the practice of reading aloud...you catch so many mistakes this way! Then, we critique on the spot. We only have 5 writers in the group, so this method is fine for us.
(I've been in groups where you submit excerpts through email beforehand, which helps the critique go faster. Plus, you have the ability to spend more time reading through each excerpt.)
It's all a matter of preference. But, the bottom line is, if you're writing, you need a support group...one that will critique honestly and one that will encourage at the same time.
All this to say that my writer's group is something I look forward to every time...definitely a favorite of mine.