Keep the card in a horizontal position on the waist level. When the thumb is on top, and the rest, except the index, from below. The index finger rests on the card side.
Make a sudden movement forward, raising a hand to the shoulder. Releasing a card, push her index finger in the opposite direction, thus spinning it. Due to such a roll it will make in the air a big circle and come back again. Substituting one hand from the bottom and another on top, catch a postcard. So she described a circle and returned, you should train.