One reason that Wicca became so popular in the late 20th century was that it did not insist on the worship of a male deity. Instead, many Wiccans favored a female deity. Some thought of Diana as the supreme being. There are two ways in which we think of and use a Goddess, firstly as an anthropomorpic representation of the unknowable and secondly as a means of storing Psychic energy for which we use the German term Vril.
First things first, once you have understood that the First Cause or the Supreme Being is beyond the thoughts of our finite minds, you might wonder why people personify that deity in an anthropomorphic fashion. Wiccans fully realize that their god-ess’ personification is only a metaphor for the Ultimate unknowable Deity. It isn’t really possible to worship that great unknown Something that may not exist. Yet human beings have a need for something to think of when they think of God. Anthromorphic images are helful in trying to grasp an unimaginable reality, remember always that they are manifestations of the unknowable.
We can trace the idea of goddess images and worship back to the very earliest time in the Vedas and we find that they are early peoples’ created images that were beyond just a representation of a living male or female. We find images of the Great Mother, for instance, with rows of breasts resembling, as Lethbridge says, gun turrets. In the Hindu iconography we see multiple images that are beyond human: goddesses with multiple heads and multiple arms and sometimes god-esses with animal parts. Thus in Wicca (as contrasted to the Abrahamic religions) we do not worship something that is at best human. We worship (or more literally grow toward) something beyond our finite comprehension.
Turning to the idea of using a goddess as a store for Psychic energy, anything exposed to strong emotions stores vril and if you have had an emotional connection to something you can name or visualize then the saying that name or thinking of the image automatically lets you use the energy stored therein.
In the cave paintings of Lascaux there is the famous Sorcerer: a male figure with a stag’s head. This could be either a priest/shaman dressing up as a totem animal or a hunter putting on a deerskin so that he could get a deer herd within spear range–or a god showing that these people recognized that the Ultimate Deity beyond simple anthropomorphic description, or perhaps the image stored vril that would help the hunter in his quest.
To summarize, then: A Wiccan may tell you, “I worship Diana” or “Lugh” or “whomever” but what they might mean will only become apparent with a close questioning of the motive in their act of “worship”