Let me start by saying that Wiccans are a very diverse bunch–only the most fundamental things about my particular faith can be assumed to apply broadly to most Wiccans. With that disclaimer, here’s the viewpoint of a solitary, eclectic Wiccan:
Deities: I believe in dual deities–a nameless God and Goddess who represent generative and nurturing forces respectively. I sometimes refer to them by descriptions related to whatever I’m currently thinking or talking about (the Mother or the Hunter, for example). Like many Wiccans, I regard the God and Goddess as representing a greater force that is beyond our ability to contemplate except in the most general terms–you might think of it as the totality of everything that exists.
Basic Tenets: These are pretty simple to state, but interpretation varies widely. We have one fundamental rule (the Wiccan Rede), and one common admonishment about consequences (the Law of Threefold Return). The Rede says,“An ye harm none, do what thou wilt”. Ditching the cute archaisms, it means “Do as you will, as long as you don’t hurt anyone”. Wiccans do not willingly, knowingly hurt or manipulate people–physically or emotionally. Some refuse to fight even in self-defense; others (including me) feel that by forcing us to defend ourselves, an aggressor has curtailed our exercise of our free will, making it permissible to hurt him as much as necessary (we don’t “will” it, we just have to do it). This is reinforced by the Law of Threefold Return, which says, “Any change you make in someone’s life, for good or ill, will return upon you threefold”. Instant (or at least quick) karma; this is really social common sense. Generally, if you’re a nice person people will like you and treat you well; if you hurt people, they’ll hurt you back. Great insight, huh? 
In addition to the formalized rules, we share an abiding love and respect for nature and firm support for equal rights for all people (and some of us define “people” very loosely).
Dogma: Wiccans aren’t into dogma; it’s a freestyle faith. Our personal rules are pretty much just interpretations of the tenets above; everyone comes to their own conclusions.
Observances: Wiccans celebrate 8 Sabbats during the year-- 4 minor Sabbats at the equinoxes and solstices and 4 major ones in between. Different solitaries and covens engage in varying levels of ritual for these occasions; I just find a place outside conducive to meditation, cast a circle (creating sacred space), and contemplate the aspects of my life that are particularly relevant to the character of the Sabbat. Some others (particularly groups) set up full altars, build bonfires, and engage in elaborate ritual and song. They like their way, I like mine; no one complains either way. Many of us also observe the new and full moons in smaller ways. We also have our own rituals for initiation into the Craft, weddings (handfasting), welcoming newborns into Wicca (with no obligation to stay Wiccan), and funerals. These are often written or modified to suit the individuals involved, particularly initiations and weddings. Many of us are self-initiated, for that matter.
Hierarchy: Huh? But…but…we’re all equal! Seriously, there’s no Wiccan hierarchy beyond the coven level. Some covens select a High Priestess or Priest to lead them in ritual; others take it in turn, or defer to whoever seems to need support at the time. Solitaries practice completely alone most of the time (duh). Every Wiccan is a priestess or priest; it’s part of the responsibility we take upon ourselves. There are no higher prelates, no bishops, no Pope–just people, doing the best they can for themselves and each other. There are individuals who are held in high esteem for their wisdom and experience, and their advice is often sought by others in the Wiccan community, but they don’t dictate the faith to anyone.
Afterlife: There’s no consensus here. Many Wiccans believe in reincarnation; others believe in an afterlife in a beautiful world resembling a perfect version of our own. Still others believe in a combination (a period of rest or an entire life in another world, followed by reincarnation into this one). There are other beliefs as well–too many to describe them all fairly. I like the rest and reincarnation theory, but I don’t believe firmly in it. In due time, I’ll find out–so why stress about it now?
Other things? Well some preemptive answers here for some common questions:
We don’t proselytize. We don’t seek converts or seduce people into our religion. If you’re interested, we’ll tell you about it, but we won’t push it on you. If you’re happy with what you’ve got, then we’re happy for you–please extend us the same courtesy.
Not only do we not recruit kids, we generally don’t teach anyone under the age of consent or let them come to rituals; there are exceptions in the cases of children born to Wiccan parents and especially mature young adults. Choosing a religion is an important decision; fairness demands that we try to make sure someone is mature enough to make it before she does so.
We’re not Satanists, and we’re not what you generally see on TV. We do work magick (I know, the extra -k looks pretentious, but it does distinguish it from stage magic), but if you look at it objectively, you’ll see that our spells are essentially prayers. We just put a lot of effort into them. Like prayers, there’s only some anecdotal evidence that magick affects the material world. It does have the benefits of calming you down and leading you to focus positively on a problem, though.
Oof, what a long post! Anything else you want to know, just ask.
Blessed Be
