Heather Moore, Michele Paige Holmes, Jeff Savage, Annette Lyon.
They meet weekly. They bring a scene 6-8 pages with copies for everybody. They read it through once, with everybody making notes on their copy. Then they go around the table and each give their report. They have a timer, since they are all good friends, and can sometime get off track.
They all feel that the critiquing helps them develop their skills, and make their books better.
You improve not just by getting your work critiqued, but by listening to others being critiqued, or by critiquing yourself.
'Pick up' groups can be ineffective, if you end up with people on different levels, or writing different genres. It's better to get to know people, find who you would like to critique with, and then make invitations.
The group then actually goes through a few critiques so we can see how they do it. One thing that impresses me is how quickly they do it (they cut the time down a bit for the presentation, but still). They clip right along. I think a timer is very important this kind of critiquing, but think it could be very effective.