The art of cold reading is something often demonstrated by psychics. The skill is in reading the responses - both verbally and physically - of their subject to non-committal questions in order to look like the psychic themselves already knows the answer. We often don't realise how much we give away about our lives from our age, gender, ethnicity, accent, vocabulary, clothing, hairstyle etc.They may be sweeping generalisations but skilled cold readers can use these heuristics to make pretty specific points that seem unique but in reality are simply statistical likelihoods
For instance, a cold reader doing a psychic show in Edinburgh where most of the attendees are well-dressed middle-aged women could safely assume that many in the audience have lost a parent - with a name like Margaret or John and likely to cancer. It would be highly unlikely they would get many 'hits' throwing out the name Genevieve or Giovani or death by heat-stroke.
Often Cold readers will throw out generalisations based on their audience "I'm getting a Margaret/Maggie/Mags/....definitely an M...Maaaary maybe?' in the hope of getting the first hit. They can then use these heuristics to ask leading questions in clever ways that the subject thinks the psychic came up with the specific knowledge when in reality the subject has done all the work inadvertently.