Choose passwords that make you happy

Update: for times when you really need to remember a password I still like this technique, for all other times — which is to say, ideally every time — I suggest using a password manager. Use a password manager to generate unique passwords for every service so long and complex that you couldn't possibly be bothered to type it and that will force you to always use the manager instead.

However, for the few passwords that you can't avoid typing they might as well remind you of something good. I have found this makes me happier.