The routine I use is:
I show the deck of cards (in the box) and I give it to the spectator. I usually do coins tricks and after, I ask the guy I gave the deck: "Do you remember the deck I gave you 10 minutes ago? Well, last night, I made a dream: I took a pack of cards, I turn it face up, I took one card out of the deck and I turn it face down. I replaced the card in the deck and I put the deck back in the box). The deck I dreamt about, you've it in your pocket. What I want you to do is to think about any card: free choice... It's done? Well, now give me the deck back and tell me the card you've just thinking of..." And you execute the trick.
That's another way to do this great trick!
Invisible Deck - Blue - Bicycle