Witchipedia

First off, you don't need to join a coven. Covens were once the primary source of training for most witches, but now you can get training from a variety of sources both online and locally. Most metaphysical shops offer training and there are many websites, including our own, which offer training programs and, of course, there are a billion books out there. A coven is nice, if you're the social type, you're not hamstrung without one.

Joining a coven is like joining any other group. You meet folks, you like them, they like you, you join their group. There may be more ceremony involved than some others, but the basics are the same. Sometimes it can be difficult finding like-minded people to join up with, but a trip to your local metaphysical shop or local Pagan Pride Day festival will be very helpful to you. You can also look on listing sites like http://www.witchlist.net and http://www.witchvox.com and many localities have their own local listing sites (Just put your state or region's name followed by the words "witchcraft" "magick" "pagan" or "metaphysical" into a search engine and see what you get).

This will help you find like-minded people, but actually joining up with them is on you. Be kind, be curious, be polite and soon you'll have an invitation to join their group. Just be sure it's what you really want.

If you’re just beginning on your Wiccan path, you may experience the difficulty in finding the right Wiccan mentor for you.

The good news is: When you find the right mentor, magick happens!

So here are some essential questions to ask yourself as you seek a great mentor for you.

Are you safe?
Safety is the most important detail here. If you don’t feel safe or you don’t trust the person who will be mentoring you, then it’s likely a bad situation. Listen to both your mind and your intuition. Do not take unnecessary risks. Leave or avoid the person. Safety first.

Do you two get along well?
The mentor-student relationship is a special one. Feeling good and connected to a mentor helps in the learning process.

Does the person abide by the Wiccan Rede?
If the person does not live according to “An it harm none,” you cannot trust that he or she will be good to you, too. Hurting others is simply wrong. If you see that the person does things that mess with another person’s will, get away from the potential Wiccan mentor.

Does the person align with the Law of Three?
Does the potential Wiccan mentor understand and accept responsibility related to the repercussions of his or her actions? The Law of Three holds that you will receive three times what you put out into the world. People who do bad things attract three times the trouble not only to themselves but to others associated with them. Get away from those who do bad things!

Is this person compassionate and respectful?
Some mentors are tyrants. A mentor who is a tyrant fails to demonstrate compassion and respect in many areas of life. If this potential mentor has no respect or compassion for others, ask yourself, “How will he/she ultimately treat me?” Avoid this potential mentor.

Does this person manipulate others?
Pay close attention. Do you see the possible mentor manipulating other people for selfish ends? It’s a fallacy that this kind of mentor will treat you “as special.” No! If the person hurts others, then at some point, such a person will hurt you, too! Avoid this type of mentor.

Does this person come highly recommended?
A rule of thumb for working with someone new is to talk with three people who have had previous interactions with the person. Certainly, you would ask about the level of the potential mentor’s knowledge. But even more important is to ask: “Would you work with this person again?” If the person does not have three people who unreservedly recommend him or her, then beware. So many people allow their desires to blind them to the truth. Do not let this happen to you. If you hear bad news about the person, heed it!

Use the above essential questions to help you find the right mentor for you.

Be safe by using both your mind and intuition.

Have a look on witchvox to search for a coven near you. They usually tell you whether they are Wiccan or pagan or otherwise, e.g Alexandrian etc. My local one is not Wiccan but pre-Wiccan traditional witches. There will be a contact e-mail address. Send an email asking whether they take initiates and tell them a bit about yourself. Some covens do not take new initiates, others are teaching covens and are happy to take new people. If they are interested they will probably tell you about the type of coven, what they do etc. If this sounds ok, arrange to meet in a neutral, public place. Have a chat, see if you get on.
If they are reputable, they won't invite you to join, you have to ask in a positive, strong way like "will you let me join your coven". Women ask the High priest, men ask the highnpriestess as a general rule of thumb but you can ask them who you should ask. You don't have to ask at the meeting, but most want you to ask at a face to face meeting, so if you want to join but didn't ask at the first meeting, then you should ask to meet with the priest or preistess or whomever they have said you should ask, and at a brief meeting ask in that occasion.

They usually go away and confer over a few weeks, ask their elders etc, they might ask you to meet their other members and the elders. They might refuse to admit you on the advice of the elders for some reason that you won't get to hear about, and it could be something unrelated to you personally, like that there is an imbalance in the male/female ratio and it would unbalance their energy, or whatever. In which case try another coven or ask if you can try again another time.

Basically, your coven is a second family, so you have to be able to get on and have roughly similar views. Also, you will perform magic together, so there must be a good feeling between you. Once you have been accepted, some covens keep you as a newbie for a while before initiating you, but some covens (maybe most or even all) won't circle with someone who is not initiated. They will then agree when to initiate you and you will undergo an initiation, the details of which are kept secret by each coven so they won't tell you in advance what to expect. They may tell you whether you are required to be skyclad (naked) or not, usually out of politeness so you can decide whether to go ahead. Beware that some covens prefer to be skyclad during all rituals, so they will probably tell you this at the outset (or you can ask) so you can decide whether you are comfortable with this or not. It's related to purity and contact with the elements, being before the gods in your pure form, but some people may be uncomfortable at this prospect. Not all covens do this.

That's the "how to do it" but the "whether to do it" is an equally pertinent question. Make sure the coven shares your basic leanings - e.g Wiccan, or traditional, pagan or whatever. See what sort of work they do and whether it interests you, and whether you have a good chemistry with them. Ask how many times they meet - they will expect commitment and it's unfair to ask to join if you can't commit to them.

If you find somewhere, it should feel like home. Good luck!