The number one piece of password advice is:
Only memorize a single complex password, use a password manager for everything else.
Gone is the time when you can plan on memorizing complex strings of characters using shift keys, letter substitution and all of that. The threats surrounding passwords, and the sheer number of things that require them, mean that human fragility is security's greatest enemy. The use of prosthetic memory is now required.
It could be a notebook you keep with you everywhere you go.
It could be a text file on a USB stick you carry around.
It could be a text file you keep in Dropbox and reference on all of your devices.
It could be an actual password manager like 1Password or LastPass that installs in all of your browsers.
There are certain accounts that act as keys to other accounts. The first account you need to protect like Fort Knox is the email accounts that receive activation-messages for everything else you use, since that vector can be used to gain access to those other accounts through the 'Forgotten Password' links.
The second account you need to protect like Fort Knox are the identity services used by other sites so they don't have to bother with user account management, that would be all those "Log in with Twitter/Facebook/Google/Yahoo/Wordpress" buttons you see everywhere.
The problem with prosthetic memory is that to beat out memorization it needs to be everywhere you ever need to log into anything. Your laptop, phone and tablet all can use the same manager, but the same isn't true of going to a friend's house and getting on their living-room machine to log into Hulu-Plus real quick since you have an account, they don't, but they have the awesome AV setup.
It's a hard problem. Your brain is always there, it's hard to beat that for convenience. But it's time to offload that particular bit of memorization to something else; your digital life and reputation depends on it.