From a deck, remove 5 sets of like pairs. Like pairs can be 2 cards of the same value and color suit, as in Five of Diamonds and Five of Hearts. Like pairs can also be cards of the same color and suit but opposite values, such as Three of Spades/Eight of Clubs and Three of Clubs/Eight of Spades. For the purpose of this tutorial, have the first set of cards be: Five of Diamonds, Three of Spades, Eight of Clubs, King of Hearts and Jack of Spades. The second set would be: Five of Hearts, Three of Clubs, Eight of Spades, King of Diamonds and Jack of Clubs.
Place the first set of 5 cards onto a table, in a horizontal line, alternating red/black.
Ask your spectator to memorize one of the cards.
Tell her to close her eyes and think of her card.
With her eyes closed, replace Set #1 with Set #2, alternating red/black. Tell her you are figuring out which one she thought of and removing it.
Have her open her eyes. Ask her to examine the pile to see if her card is there.
As she looks for her card, you can explain how you felt a strong connection and knew what card she chose the minute she named it. In reality, you do not know anything, but these cards look SO much alike, that she will not notice they are different.