Password length, even more so than complexity, is an important factor in keeping your password safe from prying eyes. Instead of thinking about a pass"word," think about a passphrase. When setting or changing a password, use a phrase intermixed with other characters to make your password almost impossible to break.
For example, when asked to create a password, instead of:
ilovepuppies
Consider using a phrase that is almost as easy to remember but much more difficult to break:
ILoveMy1Puppy!!
If you check both passwords on a password strength testing web site, like this one, you'll see a vast difference in the time it would take a computer to break the password.
ilovepuppies (3 weeks)
ILoveMy1Puppy!! (15 billion years)
This illustrates that the length of the password, along with a few special characters like upper case letters and exclamation marks, can dramatically increase the strength of your password without making it so complex that you'll never remember it.
Password Criteria
Cannot be a previously used password
Cannot contain more than two consecutive letters of the user's name
Must be at least 12 characters in length
Must contain characters from three of the following four categories
Uppercase letter (A-Z)
Lowercased letter (a-z)
Number (0-9)
Symbol (for example: !, #, $, %)