Spellow

You can use any deck, which the spectator can shuffle. You also need to prepare another card (maybe from another deck) on which it is written "THIS MUST BE IT", this is the prediction.

When you take the deck back, look at the 12th card from the bottom : this will be your key card. Do that by counting packets of 3. You can ask the spectator to look at how the deck is shuffled if your want an excuse for looking at the deck. Give then the deck a false cut.

Now ask the spectator to take about half of the deck, shuffle it, and look at the top card, which they can remember. They can then put that packet on top of the deck and give it a cut.

Next, grab your prediction without showing it, and the deck. Find your key card, and place your prediction just below it. You can then give the deck to the spectator.

They can cut to your prediction, and look at it. They'll (maybe) want to look at the next card, which is not their's. Put that card and the prediction on the side. Because of this fail, tell them to spell "THIS MUST BE IT" by dealing out cards. The last dealt card will be the spectator's selected card.