Cut a piece of invisible string about arms length.
Put a piece of tape on one end of the string and a small ball of magician's wax on the other end. The ball of wax should be about the size of a BB pellet.
Place the tape behind your ear and drape the string over your shoulder so it falls in front of you.
Stick the ball of wax onto one of your thumbnails. Don't apply so much pressure that it's difficult to get off, but enough to ensure the wax and string stay put.
Show the card in your hand to the audience. Ask them to verify it's the same number and suit as the one they chose, all the while pressing on the wax until it sticks to the finger rather than the card. If needed, use another hand to help slide the wax off the card onto your fingertip.
Ask a member of the audience to pick out any card from the deck. There are no tricks here, just let them draw a card out and have them hold it.
Take the card from the person without looking at it. Transfer the card from one hand to another and while doing so slide the wax from the thumbnail to the back of the card by using the other thumb. Try showing it to another audience member as an excuse to transfer the card.
Slide the card anywhere in the middle of the deck. Be careful not to place the card with the wax too close to the card behind it or they will stick together.
Wave your hand over the top of the deck as though you are conjuring the card to levitate out. While doing this, grab the invisible string between your thumb and side of the hand near your forefinger.
Draw the hand upward while waving the fingers gently, pulling on the string to bring the card up from the deck. Allow the card to come up slowly from the deck, but not completely.
Levitate the card that slowly rises from the deck into thin air. Amazingly, it floats right into your hand. This should look like the card wobbles around in the air as you grab at the card before it flies away.
Continue to move the hand upward with the string still between your thumb and side of your hand until the card floats in air and push the hand forward slightly until the card is within grasp.