You should be putting up strong barriers at every door into your Apple world. That means a long, unique password on your MacBook, a lengthy PIN or fingerprint protection on your iPhone, and a long, unique password for your iCloud account. Passwords should contain a mix of lowercase and uppercase letters, plus special characters and numbers, to make them as difficult to crack as possible. (And no, "Passw0rd!" isn't good enough.) Don't base your passwords on your address, birthday, or pet's name—a savvy attacker might research this information in order to get past your defenses.