Hold both hands out in front of you, palms up. Place the coin in the center of your dominant hand. (If you are right-handed, place it in your right hand).
Swiftly rotate your hands to be palm-down, while closing them. This step will take some practice, so feel free to do it without moving the coin first. Simply flip both hands so your thumbs are pointing inwards instead of outwards, while closing your hands into fists.
The first time you do this, simply keep the coin in your dominant hand. Practice this until you are very comfortable swiftly flipping your hands over and holding the coin.
Prepare to flip your hands again, but instead of keeping the coin in your dominant hand, use the momentum of the flip to toss it into your off-hand just as the palms of your hands start facing each other. This should be done in a fluid motion, and not in any way slow down the rest of the flipping or closing of your hands.
Keep on practicing until a casual observer is hard-pressed to tell when you are transferring a coin and when you are not.