Most
Wiccans and many
Witches think of the powers that be as the
Goddess and the
God. Technically, the Goddess and the God are
descendants of "the One," or together make up "the One," depending on what
myths you believe. In any case, the God and the Goddess are the male and female aspects of the
universe we live in.
The God is generally represented by the
Sun while the
Goddess is represented by the
Moon.
In Wicca, the God and the Goddess are thought of as actual entities, though Wiccans do not actually worship the Sun as the God or the Moon as the Goddess. It is safe to say that there is a great reverence for both, as well as for the Earth itself, which is also symbolic of the Mother. The elements Earth and Water are feminine while the elements Air and Fire are male, and these elements are supposedly ruled by their respective deities.
The God and the Goddess are also referred to as the Lord and the Lady, and each has three aspects based on what part of Their "lives" (the yearly cycle) They are in. The God is born as the tiny baby Sun God, and He grows into the Great Horned God, lord of the hunt and the forest, and finally He becomes the Lord of the Underworld. The Goddess, for Her part, is not ever really "born" but also has an innocent phase: the Maiden Goddess, who then grows into the Mother Goddess, and finally, the Crone or the wise or dark aspect of the Goddess. None of these points, even the birth of the Sun God, is really a "beginning"; every spoke on the wheel is just that, a particular point on an ever-turning circle. The celebrations that are held eight times a year (Sabbats) honor milestones in the life of the God as He rises and falls only to rise again out of the cauldron of the Goddess (when He is born, He is really just "recycled" in the Goddess's cauldron). The Goddess is honored on the Esbats, or the full moons, there are twelve or thirteen every year.
The elements are also subjects of honor; Earth for the north, Air for the east, Fire for the south, and Water for the west. They are not deities but more like forces or sometimes guardians, aspects of the God and Goddess. The four elements plus the Spirit (which is inside us) make up the five points of the pentagram, which as you may know is a sacred symbol for Wiccans, Witches, and many Pagans.
Most people consider Wicca a polytheistic religion, which in some ways it is and in some ways it is not. Being "Wiccan" usually denotes belief in the God and Goddess as actual entities, while some more general Witches and Pagans see God and Goddess in less humanlike ways (as I do). Still, even if you do not believe God and Goddess are real entities, you can still see the balance of female and male, light and dark, day and night, in all of the world, and you can revere it or at least appreciate it. If you want to get very technical, it is a way to worship and revere everything in existence; even when we break things down into bits and pieces that we can process, we can still understand that when put together they all make up a whole. Looking at it that way, we are not worshipping many Gods; we are simply assigning different names to aspects of Them. Some people do separate Them in their minds and think of Them as separate "people," but I personally don't and I know many feel the same, though I believe most people "personalize" the deities more than I do (I think of Them as a force of nature and just see everything in a sort of pantheistic fashion).
In Paganism there are many names for the God and the Goddess, and assigning Them names from mythology does not make Them different people; it just helps us understand and define our concepts of Them a little more. I can understand that some people would have trouble addressing one deity for all their spiritual needs; some feel the need to identify with, say, a Goddess of love. But if someone is addressing the whole of existence and there is only one "whole of existence," then everyone is addressing the same thing even if they give it a different name. This goes for monotheistic religions as well.
Most Wiccans and Witches like to have the "presence" of the deities at their special ceremonies and in their spells. Much of the time they "call" the elements too. Some people put images of their Gods and Goddesses on their altars or in their circles. These are "idols" to some, but it is not the actual piece of stone or clay that is being revered, only what it represents. Most people find it easier to ask for the presence of the deities when they have some sort of inspiration available. These things come in the form of simple stones (rounded for the Goddess, pointed for the God), ready-made God and Goddess images (can be found at many spiritual-type stores or can be self-made), candles (some use black and white, gold and silver, or red and green), special tools (athame/knife or wand for the God, pentacle or chalice/cup for the Goddess), or even special hand signals or charms. In any case, this is referred to as "invoking" and gives one the sense of being closer to the powers that be, and using the power within oneself and in the local environment (and sometimes over distance if objects have a connection to someone important in the ritual or spell) to help something to happen, to thank someone/express appreciation, or to find answers to questions. In short, the God and the Goddess are very important in everyday life.
A very important part of Wicca and Witchcraft is understanding that the deities are also part of us, and that we all possess a bit of the divine power, the divine love, and the divine knowledge that comes with being a small piece of this universe. Being Pagan is accepting this connection to this magnificent "everything" and doing what we can to protect it, use it, love it, and treat it with respect.