An easy trick that you can learn quickly.
1. Place a deck of cards on the ground. Get a participant to examine the deck and select a card. Tell them to place their card on top of the deck. Then ask them to cut the deck into five stacks. -- Keep in mind that the selected card is on top of the first stack.
2. Then by pointing to each of the stacks tell them put the deck back together, but in a different order.
3. The secret is that as you are pointing at the card stacks, and telling the participant how to place them back together, take a dash of salt and secretly drop it on top of the selected card as you point to it's stack.
4. Then lightly kick the cards, causing the cards to scatter in a somewhat straight path. (you are not trying to kick them into oblivion)
5. Look at the deck: locate the spot with the largest gap between one card and the next is the selected card.
Notes: Practice this trick before performing to comprehend how much salt to utilize, how hard to kick the cards, and how you will be able to deduce the selected card.