Setup
For this trick, you need a complete deck of 52 cards forming a Si Stebbins stack.
Start by allowing the spectator to cut the deck as many times as they want. Then have them dealing about half the deck in little chunks to give them a sense of control.
Get rid of the dealt cards, and have them now deal cards one by one. They can stop whenever they want : this will be their card. Deal 4 more cards, and allow the spectator to shuffle these 5 cards as much as they want.
For the rest of the trick, act as if you want to read their mind. Spread the 5 cards on the table, and "read the spectator" one card at a time.
You will see 4 cards of each suit, plus another card. Among these 2 cards of the same suit, the one with the bigger value will always be the spectator's selected card.