The following is a deck "stack" that must be set up ahead of time and maintained as you handle the deck. Among other things, by peeking at the bottom card, you can tell what the top card is. This allows you to perform many miracles!!
Start by dividing your deck into suits and into numerical order... Ace (top) to King (bottom).
The suits are set up: Clubs, Hearts, Spades, Diamonds (CHSD) or you may hear this referred to as "CHaSeD"
Leave the Clubs alone. Hearts: Leaving the Ace, Two and Three in the same order, move them to the bottom of the Hearts pile. Spades: Repeat with Ace - 6 and move to bottom of Spades piles. Diamonds: Repeat with Ace - 9 and move to bottom of Diamonds pile. Beginning with the Ace of Clubs, take one card from each pile and stack them on top of each other. Work left to right.
Example: AC, 4H, 7S,10D Then come back to the Club pile and repeat the process until all the cards are gone.
What you now have is a deck that is in the CHSD order and each card's value is off by three. (Jacks are 11, Queens are 12, Kings are 13)
Another example: 2C, 5H, 8S, JD
If you look at the bottom card (ex. 9S), the top card will be the next suit (Diamonds) and a value of three more than the 9. QH
With this system you always know the card selected by the spectator. Be careful not to shuffle this deck as it destroys the arrangement. You can however, cut the deck as many times as you want, as long as you complete the cut each time.
Therefore, the number setup is A, 4, 7,10, K, 3, 6, 9, Q, 2, 5, 8, J, A...