Read a person how? While I don't rule out mind reading, I feel it would take decades of practice. If you mean body language, there are books on the subject, no psychic powers required.
Easy exercise you can do, take a deck of playing cards, draw one card at a time and try to sense if its a red card or a black card. [Record results] once you get use to this, try to sense the card [ace, two, three...] After you get better at this, try to get the suit, if its a face or number card, and finally the whole card [king of diamonds, eight of clubs...] Take your time and try to picture the colour, number, suit, and card in your mind.