My trick was a sleight of hand trick that involved a card force and a false mentalism component. The effect is to know a card chosen by a spectator seemingly by reading microexpressions from their face.
The trick has multiple slight of hand components.
First, you need to shuffle the deck in such a way that you know what the bottom card is. This is done by riffling through half the deck with the same motion used to cut the cards prior to a riffle shuffle. However, when half the cards have been riffled from your right to your left hand, look at the card on the bottom of the right hand half. Then, shuffle the cards, taking care to release cards first from your right hand, keeping the card you’ve seen on bottom.
Further shuffles can be done to enhance the misdirection. It is possible to do an overhand shuffle that moves the bottom card of the deck to the top, which can then be reversed again, keeping the same card on bottom. To do this, start with do a normal overhand shuffle, but make sure that you end up with only one left (the bottom card) which you then place on top of the shuffled deck. The second shuffle should start with you pulling off the top card only with your thumb, then shuffling the rest of the deck normally. Thus the bottom card stays on bottom.
During the entire shuffling routine, make consistent I contact with the audience and discuss the mechanics of reading microexpressions. This will distract their attention from the giveaways in the shuffles (looking at the bottom card of the riffle shuffle, pulling off single cards for the overhand), which is very important. I didn’t do a great job at the banter.
You now have a deck with a known card on the bottom. The next step is forcing this card on the spectator while giving the illusion of free choice. There are a variety of forces, and I used one that is particularly easy to learn and has good angles. It is complicated to describe in words, so I will simply post a video of me performing the move.
Now you’ve forced the card on your spectator, who believes they have chosen a card randomly. Go ahead and give them the card face down and set the rest of the cards aside. Now is a good time to shift the tone of the trick to one of quiet focus. Tell the spectator to visualize their card, imagine it turning over and revealing itself, and to clear their mind of everything else. Then step through the possible card values and suits, feigning intense focus and mental strain. To enhance the illusion, I pretended to get a poor reading the first time and repeated the values twice.
Finally, you can dramatically reveal the selected card.