Cut the deck on the table, and lay one half next to the other. Grab one half in each hand, with the thumb on one side, and the middle and ring finger on the other. Using your index fingers, push down in the center of the each half. Use your thumbs to lift up the ends of each half. Release the cards from the thumb slowly, letting them shuffle together. That is called a riffle shuffle.
Perform the riffle shuffle. Let the cards in the right hand fall first. As the cards in the left hand are falling, hold back the last card with the thumb. Before letting this card fall, lift back with the thumb so you can see the face of the card. Memorize it very quickly, and then let it fall on top of the rest of the deck. You have just peeked at the top card, and can use that information in conjunction with other sleights.
Leave the deck on the table, and place your hands over it, with the thumbs on one side, and the middle and ring fingers on the other. Place the tips of the index finger on the top card (the peeked card). Pull up gently on the side of the card with the thumbs, then press towards the center of the deck and down, creating a bend in the card. That is called a "crimp." A crimped card will create a space when it is inserted into a deck, allowing it to be located again by sight or touch.
Perform the riffle shuffle again. Hold back the peeked card while shuffling, allowing it to fall back on the top of the deck, using the same motion as the peek.
Perform the riffle shuffle once more, this time bringing the half with the peeked card into the other hand. Hold back the peeked card with the thumb, allowing it to fall on the top of the deck again. That is a false shuffle -- it gives the impression of mixing the cards thoroughly, but you are in fact controlling the peeked card by keeping it on the top of the deck.
Place the deck on the table and cut the cards. The crimp in the peeked card should create a very noticeable gap in the deck. Cut the cards again, lifting them up at the crimp. After completing the cut, the top card should be the peeked card. That is a false cut. It gives the impression of cutting the cards, but in reality retains the order.
Have the spectator select a card, then place it on top of the deck. Perform the riffle shuffle, peeking the top card. Perform several false shuffles and place a crimp in the card. Give the deck back to the spectator to shuffle.
Have the spectator place the deck on the table. Locate the crimped card by sight, and perform a false cut, bringing it to the top.
Have the spectator take the deck, and place it into a loose pocket. Explain to your spectator that you are an incredibly accomplished psychic and will demonstrate your powers. Ask him questions about the nature of his chosen card. Slowly "read" the mind of the spectator before declaring that you know what his card is. Say the name of the card that you peeked, which is their selection.
To further amaze your spectator, remind him that he shuffled the deck thoroughly. Place your hand into his pocket, and remove the top card of the deck. If you have trouble locating the card, feel for the crimp. Remove the card and reveal that it is the card he selected.