> The secret, apparently, is to linger on your chosen card as you riffle through the deck. (In our conversation, Olson wouldn’t divulge how he engineers that to happen
I've done this trick plenty of times and it never fails to blow peoples' minds. I do it by taking the card I want them to see and slightly push down the card in front of it. This will cause a small break when flickering through.
When I first learned a real card trick back in 2002, the video had a "force" in it. There are quite a few different forces, I only learned one (involving fanning out the cards in such a way that the participant selects it).
Regardless of how you achieve the force, once you've got someone to select a card which you knew of ahead of time, shit just gets crazy. This is basically all of David Blane's up close street magic he does on video.
Like when he goes and asks someone to pick a card then throws the deck at the window and the card they chose is stuck on the outside of the window. No-one would notice the card stuck on the outside of the window before he threw the deck at it.
Another one was where he went to some NBA team's training and had them pick a card, then he got a basketball from a pile of basketballs and cut it open, and the card the guy picked was inside.
If you don't know that you were forced to choose the given card, it's the closest you can get to feeling as though magic genuinely happened.
I've done this trick plenty of times and it never fails to blow peoples' minds. I do it by taking the card I want them to see and slightly push down the card in front of it. This will cause a small break when flickering through.