"How-to" books on psychic readings rarely cover ethical guidelines. Due to the nature of psychic work, often involving regular interaction with people in vulnerable situations, some common sense ethical considerations are in order.
The first is some sort of disclaimer for the reading. Most people take Tarot readings seriously, but even good readers aren't always 100% accurate. One very experienced reader told me that he has observed most readings are usually about 85% accurate. Querents also need to remember to base life decisions on real events and experiences, and that although Tarot readings can offer guidance, they are not a replacement for responsible decision-making. I think that it's best to offer some sort of disclaimer, so that people remember to enjoy the reading but not rely on it as a replacement for their own best judgment.
Another issue is bad news. Some readers won't tell a seeker if a serious misfortune is represented in the cards, for example a future divorce or death. However, bad news is a part of life, and a psychic won't be considered very good or accurate if he or she doesn't address it. In fact, people come to psychics specifically during hard times, trying to figure out what's happening to them. If a reader can't handle bad news, I wouldn't recommend psychic work as a career path.
When people are experiencing difficulties in life, a psychic is a lot like a counselor or spiritual advisor. It's important to listen to the person's problems and provide emotional support, but the nice thing about psychic ability is being able to ask for guidance and help from the spiritual world. Of course, it's always good to suggest professional help if people seem to need it.
For cards representing future difficulties, it may be good to focus more on the positive, for example asking for intuition on what lessons are meant by the indicated path, and how the seeker might deal with upcoming challenges. It's important to word things carefully and remember that every card has multiple meanings, and that the worst possible meaning isn't necessarily the correct one. Even with strong intuition, things are rarely set in stone, and sometimes people are fortunate enough to turn bad situations around before the prediction ever happens.
Current or past bad news is a little easier, because many times the seeker is willing to open up somewhat. For past struggles, it's good to ask for intuition on the good that came of it -- the lessons learned, the period of new growth, finding a better job, meeting a new partner, gaining strength and personal insight, getting the kids into a better school, and other common outcomes of life's more trying times. It may also help to explore positive paths to recovery, prayers, or energy healing.
Confidentiality is also an ethical issue, but psychic readings are already quite confidential. One nice thing about psychics is that they usually don't even catch your last name, and they don't take notes. There is a reasonable expectation of privacy when seeing a psychic, as many issues discussed are very personal. My feeling is that it's acceptable to discuss readings with other psychics professionally, for example to compare the success of techniques -- what seems to help and what doesn't. But I don't think it's OK to reveal the seekers' names or other identifying information about them.
Reading for friends (or family) is another form of the confidentiality ethic. It's fun to read for friends, but you already know your friend's identity, and sometimes very personal things turn up in the cards. It's possible that your friend would rather not have that uncomfortable conversation. In that case, the reader has to weigh possible loss of the friendship against the importance of the message. It's also questionable whether the reader can be genuinely objective while reading for friends -- just like the danger of assuming the best outcome while reading for oneself, it's easy to assume the worst for friends out of fear for their safety. In some cases, it may be better to recommend a good reader, one whose ability and judgment you trust.
I also question a practice by some readers that I call "You have a curse, so pay me to remove it for you." This practice usually goes as follows: 1.) A seeker goes to see a psychic, having a hard time in one or more areas of life as usual, perhaps romantic difficulties this time. 2.) The psychic tells the seeker that there's an energy blockage or curse surrounding him or her, and that it doesn't come from God, rather it comes from another source. 3.) The reader offers to remove the curse or blockage, or pray for the seeker, for a fee of perhaps two hundred dollars. 4.) In some cases the psychic wants the seeker to come back for another session, and if the problem hasn't improved (as it usually hasn't), then the psychic offers to charge another large fee to work on the issue further. 5.) The "problem" may or may not improve for the seeker, but the psychic has earned a few hundred dollars, with no guarantee of any improvement in the customer's situation.
I've experienced this same routine from independent psychics in different cities, with no apparent relationship between them, a thousand miles apart. Even the exact wording and same price were mentioned. Others have mentioned experiencing the same routine to me. Although I'd stop short of calling it a scam, I'd strongly urge readers to avoid misleading practices. Aside from being unethical, it'll drive customers away. Seekers who don't experience a small miracle in exchange for such a high dollar amount will likely never return. It may be good for your competition's business, though. I can understand the feeling that good psychic work deserves decent compensation, but building up your customer base by giving good readings lends itself to a more stable business model.
One of the toughest ethical issues to deal with is obsession. Some seekers are emotionally vulnerable due to current misfortunes, for example financial problems, unstable romantic relations, or a serious disease. Some readers are fine with performing frequent readings if asked, even though it's probably more than most seekers can afford, and frequent readings would do little good. In the case of reading requests that are much too frequent, it is perfectly acceptable to limit the seeker to once every few weeks, once a month, or even drop the seeker entirely if the reader doesn't feel comfortable with the situation. Encouraging the seeker to stay focused on positive action between readings may help ease emotional dependence on the reader, for example meditation, manifestation exercises, or other self-help techniques.
One exception may be seekers with health problems, who may be helped by readers who also incorporate energy healing or other alternative health practices into their sessions. It may also help seekers feel better between visits by encouraging them to make an effort toward healthier eating habits, or other lifestyle improvements (like exercise) recommended by their health care professional.
Finally, another ethical problem is misleading advertising. Whether it's health products, psychic readings, or even hair care products, it seems some mass marketer shows up and turns a field into his own personal money-making venture. The method is usually a blitz of intense TV advertising, until the revenue stream runs dry. A few years ago, one of the targets for mass marketers was psychic Tarot readings.
One young reader told me why she won't call 900 numbers for Tarot readings. A friend of hers worked a low-paying job for a big psychic 900 number, and told her that all readings at that particular company were pre-fabricated and staged -- nothing was psychic at all. So her friend quit the job, feeling like a fraud. A more prominent case of false advertising was the television commercials leading people to believe that a psychic, "Miss Cleo," was highly accurate with callers on very sensitive personal issues (again targeting the vulnerable) -- for example, whether their spouses were cheating, the real father of a caller's child, etc. A subsequent lawsuit later revealed that Miss Cleo was an actress, not a psychic, Cleo wasn't her real name, and even her Jamaican accent was faked (she's American). Since that lawsuit, psychic readings aren't advertised nearly as much, but the problem could return. Psychic reading scandals discredit those who actually take the time and effort to learn Tarot divination techniques. Genuine readers lose business to these huge money-making operations, although the big companies do help advertise Tarot readings in general.
... And for those seeking a good reading, ask a friend! Referrals by real people are a great way to find a talented psychic in your local community.