Effect:
The performer has a pack of cards and give a second pack to a spectator. They both shuffle their packs. Each of them then chooses a card from their own pack only to find that they have chosen the exact same card.

Before you begin the trick:
Use two packs of cards with different backs so they can be told apart. Tell the spectator that this trick is all about following your lead and copying what you do.

Here's how it's done:
You (the performer) shuffle and cut your pack of cards and ask the spectator to do the same with theirs.
You then both swap packs and shuffle again.
Swap over packs once more BUT as you do so, keep the pack face down as you give it back to the spectator. Do this by holding the pack with your fingers at one end and thumb at the other and as you lay it down on the table be sure you glimpse the bottom card (eg. 5 hearts).
 
You say: "Just follow my lead and copy what I do"

Spread out your own pack face down in a ribbon.
Take a card from the middle and look at it saying you're going to memories it (you don't need to in fact!)

You say: "Now you take a card and look at it"

Take your face-down pack, square it up and put your chosen card on top face down.
Ask the spectator to do the same.
Take your cards and cut them so that your chosen card disappears in the pack.
Ask the spectator to swap packs again.

Tell them to take from your pack the card they memorized and put it face down on the table.
Spread the cards out on the table, face up and towards you and look for the card that you glimpsed at the beginning of the trick (5 hearts).
When you've found it, the card underneath it will be the spectator's chosen card.
Take it out, put it face down in front of you and ask the spectator to show their card.
They turn over their card.
You pause and then turn over yours.
They're identical.

"You really did do as I did!" or "You really did follow the leader!"