One more hint: when you go to a festival, of course see and hear as broad a variety of performers as you possibly can, but stay after!! This may mean the parking lot area, or camping if people stay over, or sticking to someone who has been there many times, to find where folks go after, or even volunteering for cleanup duty. The performers at a festival will often be making the effort to present unusual material, but the informal gatherings afterward tend to be filled with the 'classics' that folks have loved for years and that 'everybody' knows and can sing along.