The Ethics of Reading
Tarot readings touch on people's real situations and emotions, so when you read for others in particular, some practical boundaries are worth spelling out, beyond questions of card meaning.
Tarot is not a diagnostic tool
Tarot cannot replace professional medical, legal or financial advice. For questions about health, lawsuits or investment decisions, tarot can help sort out a person's state of mind and situation, but the actual decisions should be left to professionals in the relevant field. When a querent arrives with a question like this, the more responsible course is to say clearly what tarot can and cannot offer inferred.
The limits of responsibility: questions about yourself vs. about others
As How to Ask a Question mentions, questions about things you can control suit tarot better than questions aimed entirely at other people. The ethical reasons go further. Giving a definite answer to questions like "Do they really love me?" or "Will they be affected by the spread I laid out?" can override the other person's right to judge their own situation, and it can easily turn into a tool for steering other people's decisions. The more responsible course is to guide the question back to the choices the querent can make themselves inferred.
Cold reading and suggestion
What the reader says affects how the querent understands things and acts afterward. This is the mechanism by which tarot really works as a tool for reflection, and it is also something to be careful with. Statements so general that they are "right whichever way you read them" (a common cold-reading technique) may seem "very accurate," but they offer nothing actually useful. Wording that is too certain, catastrophic or overly optimistic can have an unnecessary effect on the querent's current state of mind. Leaving room in your wording and avoiding absolute statements is practical advice stressed again and again in this craft inferred.
How to talk about difficult cards
Drawing a card that looks "frightening," such as Death, The Tower or The Devil, does not mean disaster in a literal sense. The core meanings of these cards are transformation, breaking through illusion and facing what binds you (each card's page explains this in detail). Explaining the meaning clearly and avoiding sensational literal associations is something to take special care with when reading for others.
The limits of what a reading can do: beware of false claims
A tarot reading affects what the querent thinks and does next, as the section on cold reading and suggestion above already noted. That influence should not be mistaken for "the cards have some supernatural power to control events." One thing to be wary of is that some practitioners attract clients with near-false advertising, claiming they can make "estranged couples certain to reunite," "bring about a quick and happy marriage," "lift any kind of bad luck," "break curses" or provide "spells or amulets that bring luck." Claims like these dress tarot up as a magic tool that rewrites real-world outcomes directly. Tarot is a tool for reflection that helps people sort out their situation and see their options. The more absolute these claims are, the less they hold up, and the more they invite skeptics to dismiss the whole field along with them. The occasional popular belief that "a certain card is a 'wish card,' and drawing it makes your wish come true" is the same kind of misunderstanding. What actually has an effect is that a clearly stated hope changes where the person puts their attention and what they do next. The card works more as a prompt for reflection and for focusing intention; it cannot produce a result on its own inferred.
A similar misunderstanding can appear on the client's side. Some querents give the reader's words too much weight, believing that if the reader says "you will succeed, be happy, have it all," it will happen by itself, while failing to see that the chance to bring about those results has been in their own hands all along. The reader's role is to help point out where the opportunities are. Producing the result for the querent is outside that role.
Being clear about what tarot can and cannot do is the foundation that lets this craft stand up as long-term work. Tarot can help the querent sort out their situation, see their options and focus vague thoughts into a direction they can act on. It cannot replace professional judgment (legal, medical, financial), and it cannot, like "magic," single-handedly undo what has already happened or guarantee that a certain result will come about. Overselling what a reading can do may make for a better gimmick in the short term, but in the long run it uses up the credibility of the reader and of the whole field.
Privacy and records
If you put readings into a personal wiki or notes (as in the daily-card journal described in Your First Reading), consider anonymizing specific information about third parties (names, identifiable private matters). This is general privacy practice and applies well beyond tarot, but it is especially easy to overlook in readings, since a record of a spread often comes with specific people and events written down alongside it.
Points to watch when reading for yourself
A common problem when reading for yourself is "selective belief": accepting the cards that match what you hope for, and reshuffling and drawing again when they don't. This makes tarot lose its value as a reference inferred. A sounder practice is to write the question down clearly and settle on the spread before drawing, then read whatever comes up all the way through, even if the result is not what you wanted.