While at the Gym the other day, I was working with my combination lock, and realized something that would be useful to me as a programmer. To wit, my combin
First of all make sure the password is long. Consider using a "pass-phrase" instead of a single "pass-word". Breaking pass-phrases like "Dogs and wolves hate each other." is very hard yet they are quite easy to remember.
Some sites may also give you an advice which may be helpful, like Strong passwords: How to create and use them (linked from Password checker, which is a useful tool on its own).
Also, instead of trying to create easy to remember password, in some cases a much better alternative is to avoid remembering the password at all by using (and educating your users to use) a good password management utility (see What is your favourite password storage tool?) - when doing this, the only part left is to create a hard to crack password, which is easy (any long enough random sentence will do).