Don't carry your PIN number where you keep your ATM card.
Never write your PIN number where it can easily be lost or seen.
Periodically check your account activity. Compare the current balance and recent withdrawals or transfers to those you've recorded, including your current ATM card withdrawals and purchases. If you notice transactions you didn't make, or if your balance has dropped suddenly without activity by you, immediately report the problem to your card issuer.
Debit card for teens? Yes, a pre-pay card is an excellent way to teach teenagers how to manage a credit card. There's little worry about going over-limit, because the amount that may be charged is prepaid.