Often Traditional Wiccans are asked to describe our religion and beliefs for interested people, who may or may not have confused us with other Pagan religions, with inversions of Christian/Islamic religions like Satanism, or with purely magical traditions with no religious base. There is a lot of flexibility in the ways that we describe ourselves, and one characteristic of Wicca is a large degree of personal liberty to practice as we please. Still, there is an outline that can be described in general terms. Many traditions will depart from one particular or another, but groups departing from all or most of these features are probably non-Wiccan Traditions attempting to stretch or distort the Wiccan name to cover what they want to do.
Wicca is an Initiatory religion descended from the Ancient Mystery Religions. A mystery religion is not like Catholicism where a Priest is the contact point between the worshiper and the Deity, nor like Protestantism where a sacred Book provides the contact and guidelines for being with the divine. Rather a Mystery Religion is a religion of personal experience and responsibility, in which each worshiper is encouraged, taught and expected to develop an ongoing and positive direct relationship with the Gods. The religion is called a "Mystery" because such experiences are very hard to communicate in words, and are usually distorted in the telling. You have to have been there in person to appreciate what is meant. Near and far-Eastern religions like Buddhism, Hinduism, Taoism and Shinto are probably Mystery traditions, but Wicca is very western in cultural flavor and quite different than eastern religions in many ways.
Most Wiccan Traditions, .K.A.M. included, have particular roots in the British Mystery Traditions. This includes traditions of the Picts who lived before the rise of Celtic consciousness, the early Celts, and some selected aspects of Celtic Druidism. American Wicca is directly descended from British Wicca, brought in the late 1950's by English and American Initiates of Gardnerian, Alexandrian and Celtic Wicca. These traditions are a little like the denominations in Christianity, but hopefully far more harmonious.
While British Traditions are very strong in Wicca, or the Craft as it is sometimes called, other Western Mystery traditions feature prominently, including the ancient Greek Mysteries of Eleusis, Italian Mysteries of Rome, Etruria and the general countryside, Mysteries of Egypt and Persia before Islam, and various Babylonian, Assyrian and other mid-eastern Mysteries that flourished before the political rise of the advocates of "one god".
Wicca, Witchcraft, and "The Craft" are used interchangeably at times by many kinds of people. It is fair to say that all Wiccans are Witches, and many of us believe we are the only people entitled to the name. It is important to know that many people call themselves witches who are not in the least Wiccan, and that Masons also refer to themselves as "Craft", with good historical precedent. Carefully question people on the particular things they do and believe as part of their religion rather than relying on labels. Any real Wiccan would welcome such honest inquiry.
There are specific Wiccan beliefs and traditions, including worship of an equal and mated Goddess and God who take many forms and have many Names. Groups who worship only a Goddess or only a God are not traditional Wicca however they may protest, although they may be perfectly good Pagans of another sort. The Wiccan Goddess and God are linked to nature, ordinary love and children -- Wicca is very life affirming in flavor.
Because we have and love our own Gods, Wiccans have nothing to do with other people's deities or devils, like the Christian God or Satan, the Muslim Allah or the Jewish Jehovah (reputedly not his real name). Christians often deny this fact because they think that their particular god is the only God, and everybody else in the whole world must be worshipping their devil. How arrogant. They're wrong on both counts.
Traditional Wicca is a religion of personal responsibility and growth. Initiates take on a particular obligation to personal development throughout their lives, and work hard to achieve what we call our "True Will", which is the best possibility that we can conceive for ourselves. Finding your Will isn't easy, and requires a lot of honesty, courage and hard work. It is also very rewarding.
Wicca is generally a cheerful religion, and has many holidays and festivals. In fact, most of the more pleasant holidays now on our calendar are descended from the roots Wicca draws on, including Christmas, May Day, Easter and Summer Vacation. Wicca is definitely not always serious. Dancing, feasting and general merriment are a central part of the celebrations.
Wiccans have ethics which are different in nature than most "one-god" religions, which hand out a list of "do's and don'ts". We have a single extremely powerful ethical principal which Initiates are responsible for applying in specific situations according to their best judgment. That principle is called the Wiccan Rede (Old-English for rule) and reads:
Based on the earlier mention of "True Will", you will understand that the Rede is far more complex than it sounds, and is quite different than saying "Do whatever you want as long as nobody is hurt". Finding out your Will is difficult sometimes, and figuring out what is harmful, rather than just painful or unpleasant is not much easier.
People become Wiccans only by Initiation, which is a process of contacting and forming a good relationship with the Gods and Goddesses of Wicca. Initiation is preceded by at least a year and a day of preparation and study, and must be performed by a qualified Wiccan Priestess and Priest. The central event of Initiation is between you and your Gods, but the Priestess is necessary to make the Initiation a Wiccan one, to pass some of her power onto you as a new-made Priestess or Priest and to connect you to the Tradition you're joining.
Women hold the central place in Wicca. A Traditional Coven is always headed by a High Priestess, a Third Degree female Witch with at least three years and three days of specific training. A Priest is optional, but the Priestess is essential. Similarly, a Priest may not Initiate without a Priestess, but a Priestess alone is sufficient. Women are primary in Wicca for many reasons, one of which is that the Goddess is central to our religion.
People often ask "Can I become a Wiccan and still remain a Christian, Muslim, practicing Jew, etc. The answer is no. The "one god" religions reject other paths besides their own, including each other's. "One-god" religions also do not exalt the Female as does Wicca, and mixing two such different traditions would water them both down. Besides, you'd have to ask how serious a person who practiced two religions was about either one. Being Jewish is an exception, since it is a race and culture as well as a religion. There are many Wiccan Jews, but they practice Wicca, not Judaism.
People interested in Wicca are usually curious about the magick that Wiccans can do. While magick (spelled with a "k" to distinguish from stage conjuring) is not a religion in itself, it is related to our religious beliefs. Wiccans believe that people have many more abilities than are generally realized, and that it is a good idea to develop them. Our magick is a way of using natural forces to change consciousness and material conditions as an expression of our "True Wills". Part of becoming a Wiccan is training in our methods of psychic and magickal development.
Because we believe that everything a person does returns to them magnified, a Wiccan will not work a magick for harm, since they would pay too high a price. But a helpful magick is good for both the giver and receiver! Wicca is entirely compatible with the scientific method, and we believe all the Gods and forces we work with to be quite natural, not supernatural at all. We do not, however, hold with the kind of scientific dogma or pseudo religion that sees everything as dead matter and neglects its own method by trumpeting "facts" without honest examination of evidence.
Long ago the spiritual (and sometimes physical) ancestors of Wiccans were Priestesses and Priests to the Pagan culture as well as devotees of their Mystery. Now that a Pagan culture is rising again, some ask if today's Wiccans could resume that role. This seems unlikely.
Today's Pagan culture is very diverse and more interested in exploring and creating new forms than in building on existing traditions. A public role would either dilute our traditions or force them on an unwilling audience. The neo-Pagan community generally prefers "media figures" and rapid membership and growth. This is not compatible with our slow methods of training and Initiation, the insistence that livelihood come from work outside the Craft, or our needs for privacy. Our religion is not accepted in the American workplace or political system, and may never be. The most powerful Priestesses are often unknown to all but their Coveners. While all Wiccans are Pagans, all Pagans are not Wiccan, and it is best that it remain so.