Divination (with tarot or any other oracle) seems to be most effective when one is in a relaxed, meditative, and spiritually receptive state of mind. Having done this sort of thing for many years, I usually find I just naturally slip into the right sort of mood when I prepare for a reading. However, when I began my practice, I would often create a suitable atmosphere by lowering the lighting, burning a candle or two, some incense, and doing some breathing work to help me ground and center. I still do these things some times, when I want my work with the cards to feel more spiritual and special.
When reading for others, I don’t do so much to set the mood. Every client has different expectations, and too many trappings can be distracting, or even feed into negative stereotypes the person may have about “fortune tellers” of a certain ilk. That said, it is nice to have a candle burning, and to create a calm environment. Calming can be just a matter of what you do with your own energy before and during the reading.
I’m not much of a fan of music during a reading. Silence has a timeless quality that feels right when doing this sort of activity. Ideally, a reading should be done in a private, secluded space. This is obviously not possible if you are working at a fair, party, or other large gathering. But once again, your personal energy, if grounded and centered, can help lessen the sense of commotion around you.
Although no special trappings are needed to have an excellent divination session, I do think it is nice to do a little something that reminds me that this is a spiritual practice, and is set apart, however lightly, from the bustle of daily life.