Use passwords of eight characters or more with mixed types of characters. But even passwords with common substitutions like "dr4mat1c" can be vulnerable to attackers' increasingly sophisticated technology, and random combinations like "j%7K&yPx$" can be difficult to remember. One way to create more secure passwords that are easy to recall is to use passphrases -- short words with spaces or other characters separating them. It's best to use random words rather than common phrases.
For example, "cakes years birthday" or "smiles_light_skip?"
Avoid using the same username/password combination for multiple websites. Especially risky is using the same password for entertainment sites that you do for online email, social networking, or financial service sites. Use different passwords for each new website or service you sign up for."