I'm not especially a group person. Too much of a loner and I like to do things my own way which is not always conventional or sensible to everyone. Sometimes it only makes sense to me and sometimes I turn out to be wrong, really wrong even. But, that's getting sidetracked. I've begun looking at writing groups for myself.
Generally they fall into two groups, those which are genre specific and those which are location specific. Chances are you won't find a group which is in your geographic area and caters to your writing genre, in the same group. (Unless you live in a large city). If you look for your genre it is likely to be an online group. This has good and bad points, of course. A local group will meet in person on a schedule but you may find little support and information for your genre. Don't get discouraged, the main thing you are looking for in a group is support after all. If you can find that online or in person that is the best thing.
Do make sure the group has a set goal in mind and does keep to it. A group for coffee and conversation is nice but you need more than socializing. If you want a review/ critique of your work find out what the rules are for both writers and readers and beware of handing out your work and not getting it back or having it copied. What do they have set up and are you feeling ok to trust others with your work in progress?
Overall, stick to getting support and information. Whatever helps you to stick with your writing goals and make you feel you are on the right track. A writing group is especially good for those who don't have support from family and friends.
To get you started, I used to maintain this Dmoz category
with writing groups and organizations. I no longer maintain it but it is still a good start point.