sorority: types, rush info [need info please]

Hi-new transfer student.
I was wondering if anybody could tell me the do's and don'ts of rushing at Berkeley?

Also...how important are looks in the different sororities? I know some of them care about connection more than looks...and others are pretty superficial.
So can anyone give me the pros and cons of each sorority?
I've been looking all over every one of their websites, but I don't really know exactly how to distinguish between them (because a lot of them say the same things about sisterhood, bonding, philanthropy, etc).

If someone could help me out that would be MUCHHH appreciated! :]