Magic is just another form of storytelling, so It's always nice to follow a classic approach :
- Introduction : You introduce yourself and the premise of the routine. In the process, the spectator selects a random card.
- The inciting incident : The card is seemingly lost under very fair conditions.
- Tension building : You attempt to retrieve the card in a completely impossible manner. This is when you have to build a lot of tension, like "Do you remember that card I asked you to hold in your hands ? Do you think it would be possible that bla bla bla ?". At this point, you have to sell the total impossibility of your act. They are not accustomed to see our routines, so you'd better explain them clearly why you're going to break the laws of physics.
- The revelation : You turn the card over, you open your wallet with your card inside, or any revelation.
The point is : don't rush the moment. You're telling a story and if it is well told, the revelation will have a great impact.
As for specific hard-hitting card revelations, Card to Impossible Location is always great, misdirection revelation is also really good (card under the glass, on your forehead), spectator dead cutting to his own card too... At this point, it's a matter of taste. But as always, it's your presentation that really makes an impact.