This instructable well teach you how to do that.
Step 1: Beginning
A deck of cards. I recommend ellusionist.com
First, make sure that the desired card you want to "find" is at the top of the deck. Hold the deck in standered mechanics grip.
For those of you who dosen't know what that is, it's when you hold a deck with your thumb on one side, index finger on the top, and your other three fingers on the other side.
Hold the deck face down in mechanics grip.
SECRET OF PREFORMING THE MOVE:
Usually, the mechanics grip is natual, and shouldn't feel funny. This time, shift your 3 pinky-middle fingers to cover more of the card.
Step 2: The Pull
Do this fast, or people will be able to see.