Want to know how I never forget to take back a credit card, driver’s license, or whatever after having to hand it over to someone? You know, say you have to hand a card over to a teller or someone, then you get your receipt and start walking out of the branch and they have to run after you going, “Sir! Sir! Your card!”
My trick is that if I have to take something out of my wallet, I never put my wallet away until I make it whole. There’s simply no way to walk away from somewhere with your wallet still in your hand. You’ll want to put it away, but when you do, you’ll think, “oh yeah, dude still has my card.” And every once in a while you’ll be like, “huh, why do I still have this in my hand?” and you’ll go to put it away and then remember why it’s out–and that keeps the fact that someone else has your card in the forefront of your memory.
When you take the card or whatever back, put it in your wallet, and put the wallet away.
Of course, this applies to whatever situation. Wallet is merely an example, but it applies to purses, portfolios, back packs, etc.