1. Basics of Passwords

• Use at least 8 characters, the more characters the better really, but most people will find anything more than about 15 characters difficult to remember.
• Use a random mixture of characters, upper and lower case, numbers, punctuation, spaces, and symbols.
• Don't use a word found in a dictionary, English or foreign.
• Never use the same password twice.

2. Things to Avoid

• Don't just add a single digit or symbol before or after a word, e.g., "apple1".
• Don't double up a single word. e.g. "appleapple"  
• Don't simply reverse a word. e.g. "elppa"  
• Don't just remove the vowels. e.g. "ppl"  
• Key sequences that can easily be repeated. e.g. "qwerty", "asdf" etc.  
• Don't just garble letters, e.g. converting e to 3, L or I to 1, o to 0. as in "z3r0-10v3" 

3. Tips for a Strong Password

• Choose a password that you can remember so that you don't need to keep looking it up, this reduces the chance of somebody discovering where you have written it down.
• Choose a password that you can type quickly, this reduces the chance of somebody discovering your password by looking over your shoulder.
• Don't use passwords based on personal information such as name, nickname, birthdate, wife's name, pet's name, friend's name, home town, phone number, social security number, car registration number, address, etc. This includes using just part of your name, or part of your birthdate.
• Don't use passwords based on things located near you. Passwords such as "computer", "monitor", "keyboard", "telephone", and "printer", etc are useless.
• Don't ever be tempted to use one of those oh-so-common passwords that are easy to remember but offer no security at all. e.g. "password", "letmein".
• Never use a password based on your username, account name, computer name, or email address.

4. Choosing a Password

• Use good password generation software.
• Use the first letter of each word from a line of a song or poem.
• Alternate between one consonant and one or two vowels to produce nonsense words. Adding special characters and numbers will enhance security. For Example: NH^hg76NJ***J90
• Choose two short words and concatenate them together with a punctuation or symbol character between the words. For example: electric#%sudden

5. Changing Your Password

• You should change your password regularly. Once a month is reasonable for most purposes.
• You should also change your password whenever you suspect that somebody knows it, or even that they may guess it, perhaps they stood behind you while you were typing your password.
• Remember, don't reuse a password.

6. Protecting Your Password

• Never store your password on your computer except in an encrypted form. Note that the password cache that comes with Windows (.pw; files) is NOT secure, so whenever Windows prompts you to "Save password", select NO.
• Don't tell anyone your password, not even your system administrator.
• Never send your password via email or other unsecured channel.
• Yes, write your password down but don't leave the paper lying around, lock the paper away somewhere, preferably off-site and definitely under lock and key.
• Be very careful when entering your password with somebody else in the same room.

7. Remembering Your Password

Remembering passwords is always difficult and because of this many people are tempted to write them down on bits of paper. As mentioned above this is a very bad idea if the paper is not stored under lock. So what can you do?

• Use a secure password manager.
• Use a text file encrypted with a strong encryption utility.
• Choose passwords that you find easier to remember.

No passwords mentioned here are safe to use, because these have been published on this page, so assume hackers have these passwords already and they will use these to check. So, ensure to generate your own passwords using above instructions, but don't use the same passwords mentioned in above article.