After every session, the Tarot reader should write his results of divination in a journal. A journal is a good way to check the accuracy of a reader because when an event occurs he can see if he had predicted it. Another practical reason to use a journal is for reference and memory. When a querent cannot remember whether he would receive a large check in the second week of November or in the last week of December, she can simply contact the reader and his mini summary of her reading.
Now I must remind all readers to be serious about this skill. During a reading there should be quietness and tranquility. Tarot is a trip to the realm of, quite briefly, magic. Why taint it? It is not a game to play on a boring Friday night, so please do not treat it as such. Have reverence for a fascinating pagan art form.