Most Witches today who wish to follow the Pagan ways learn from books, and practice alone, either by choice or by circumstance. These men and women are usually referred to as “solitaries”, and can practice Sabbats and rituals in much the same way as a coven would, but alone. This allows a great deal of freedom, but may lack a feeling of community and support.
When Witches talk about a Coven, they are referring to a group of men and women who study and perform rituals and sabbats together, usually including initiation into an established Tradition. Suffice it to say it is generally a small group that can work together very closely. For a coven to be strong, the energy contained within must be “in sync” and all members must feel comfortable and trust the others. This provides for the “group mind” of the coven, which allows coven members to work with the force of the group, even when physically alone.
Coven members are responsible for various aspects of each ritual, so there is less autonomy than there is for a solitary, and membership in a coven is a great responsibility and commitment. On the other hand, covens enjoy a sense of family and community and together can raise great energy. Most covens require that a neophyte or dedicant go through a period of training before sharing in ritual.
I practiced as a solitary for many years before I found others in my local community who I felt comfortable joining in ritual with. I began celebrating the Sabbats (the eight major holidays of the year) with an open circle called the Solar Circle. Unlike the typical coven, this circle meets at the major holidays only, and is open to all who come with an open mind and respect.
In 1999, I was initiated into a Traditional Wicca coven, and after several years of study and work, elevated to 3° High Priestess in this Tradition. As a regional Clan Head, I train students in my coven and supervise study groups and covens downline from me (ie. groups led by my former students).
If you are interested in finding a local group to celebrate or study with, I suggest looking through the listings at WitchVox’s Witches of the World. Try going to a few open events first, if you are new to the community, to get a feel for the various personalities and energies in your local pagan community. You may also learn that you are drawn to paths other than the widely-written-about path of Wicca, such as Asatru, Neo-Druidry, Neo-Shamanism, or the feminist Goddess Movement.