Guardian of the Deck
Guardian card is your connection with your tarot deck. Every Tarot deck should have its guardian card chosen from major Arcanas in a ritual way. This is not only Guardian card of the deck, but the link between deck and practitioner who owns the deck with his specific character, energy, personal preferences and abilities. You will do this once and only once with each deck you start using.
It's not necessary, but if you want more serious work with Tarot, I recommend you to find Guardian Arcana of your deck. That card is your personal guide through the deck and you'll see that card appearing more often in spreads, especially if you do tarot readings for your self. Meditating on that card opens you to its specific symbolism which is significant for you, and for a deeper understanding of every other card in the deck. Practicing this, you may find out many things about yourself that you were not aware of. Of course, this is a valid claim for meditation on each card, but that one is the most important for you in meeting with specific deck.
For most of the people, free access to studying tarot should be a quite positive experience. This is the art in some way and in that sense freedom of thinking and expression is more than welcome. Besides some common explanation you may find in every tarot guide it is imperative to start developing your own way of thinking, understanding and linking terms, symbols and impressions. However, every art has it's tools and ritual and meditation are tools of tarot reader and as such should be taken seriously.
How to find your deck's Guardian card
The procedure is simple. First, you need to get tarot deck. It's the best to use your personal deck, not borrowed or already used by another person. Especially don't get the deck from a person who you suspect or are not sure in her intentions towards you. Don't use deck if you don't know who was the previous owner. You need a new, innocent and energetically clean thing. If you get already used tarot deck you can never surely know what was the state of mind of the previous owner, what were her thoughts while she used it, was she filled with negative energy, negative projections or psychically unstable. If you really have to use the used deck, try to do some energy cleaning, as explained in below, before you start to use it. Tarot deck is the personal thing the same as underwear and you don't want to borrow or share your personal stuff.
So, after you get your deck, connect with it, and try to keep in contact with it. It is a live creature like crystals for instance. Actually, much of potency of tarot deck comes from connection with the person who is using it. It becomes alive when it gets into owners hands. Look at your deck and cards, meet with them, gaze into them, touch them, one by one, keep them in hands and so... Keep your deck under the pillow while sleeping or keep them in hands while relaxing. While sleeping or in a relaxed state the mind is empty, energy flows free so you feel clean of external influences. If you want to practice this it is much better to keep deck wrapped in silk bag or piece of silk cloth instead of keeping it in original box. Define a period of meeting with cards at your own discretion, general guidelines are between one week and one month. For example, you can use period of 28-29 days and use Moon phases for orientation. Moon is connected to intuition, dreams and all occult disciplines, and as such is a good ally in tarot science. After that, you and your deck are ready for symbolic ritual consecration.
Determinate the day for your ritual. Try to be relaxed, unburdened with daily issues, make the atmosphere that is most pleasant for you. If you wish, light up the candles, if you have any crystals put them around you and do whatever would make you feel more in a sacred and ritual mood. If you don't like it, don't do it. The most important thing is to feel comfortable and peaceful. Segregate only major Arcanas from the deck. Sit comfortably and spend a few minutes in deep relaxation breathing and when you feel ready shuffle the major arcana in your hands with strong intention to find out the guardian of the deck. If you are in a mood, talk to your cards like to living being and refer to them to show you the guardian card. You may shuffle card in your hands then cut and open the next card or mix them on the clean flat surface with both hands and pick the one from the pile. You can try to keep your both hands open above the cards for a while and try to feel energy and connection. Let the cards guide your hands. It is not necessary but if you have an experience in work with energy or practice any of energetic exercise it can't do any harm to try it on cards. And please remember, do it only once. Go into it without any expectation to pick the wished card. All of them are equally worthy and respect them. You may pick a card which seems not so impressive or attractive to you, such The Chariot or Justice for instance, but that is for the reason. If you pick some, at a first sight, not such a positive card like The Tower, The Devil, The Hanged Man or The Moon, that is for the reason too. That is your guardian card and respect it. As you go deeper and deeper trough symbolism you'll find that all of them are interesting and overflowing with meanings. Be thankful for your guardian card. And, good luck on your journey!