I'll start out with an extremely basic card finding magic trick. It is known by a lot of people, but it is also very easy, and people tend to learn easy tricks.
The effect: A card is chosen at random from the deck of cards. The performer, at no time, can see what the card is. The card is cut into the deck, and the performer then finds the card.
It may sound simple, and it really is. The thing about magic, is that it is as big as what you make it. If you act like it's a miracle, people will think it's a miracle. With that said, this is not the most visual or effective trick. It's a great opener for a routine, but not too much more. In the variation of this, you can make this into a really effective bar bet.
This uses a 'key card' or 'locator card'. This means that you have a card within the deck that will somehow aid you in finding another card.
How to do it: Your spectator chooses a card, and while it is being memorized and seen by everybody, you look at the bottom card of the deck and remember it. When the audience is ready to put the card back into the deck, you have them put it on top and then the deck is cut. The card is, more or less, lost in the middle of the deck.
But what your spectators don't know is that the card that used to be on the bottom of the deck, is now directly above the card they put on the top of the deck.
There are a variety of reveals here, but a good traditional one would be to fan through the cards face up, and locate their card by looking one above the card you memorized earlier. This, however, is just the way the trick is done, not the presentation. If you want to make it seem like you can locate their card with your superior sense of smell, be my guest. The key to this trick, is to make something of the trick instead of just finding their card. Make a show out of this by making a joke, or telling a story with the cards.
VARIATION: My mom did this one before her untimely death. The trick is done like usual, but after the deck is cut, you flip the cards onto a table face up, one by one. When you reach your key card, you know that the next one is their card. You flip their card onto the table face up and then grab the next card from the deck as if you are going to flip it over to. Then you make the audience a bet that the next card you flip over will be the chosen card. They (hopefully)take the bet, thinking you messed up. When they agree, you put down the card you have in your hand, and flip over their face up card, which they thought you had missed.
