Passwords should be 8-14 characters in length. The most secure type of password includes a combination of upper and lower case letters, along with numbers and symbols. For instance, A$f8T3B#w5xG would be a very difficult password to crack, even with a brute force attack from a very determined hacker.
Try to avoid using common words in English or other languages, as well as obvious things like your name, a relative’s name or other words that might easily be guessed by an unauthorized user. Here are examples of bad passwords:
- any person’s name including yourself, partner, children, relatives, friends, etc.
- your birthday
- your Social Security Number, telephone number, address, etc.
- words or combinations of words from a dictionary, English or any other language
- numeric sequences, e.g. “1234”
- words spelled backwards
Finally, never under any circumstance make the password the same as your username or use a password such as “username”, “password”, “admin”, “test”, “guest”, etc.
The Password Meter is a great tool that you can use to check the strength of your password.
Google posted a great write-up on how to create good passwords.