I have found it helpful to create patterns on the keyboard that can be moved around the keyboard. Basic example: 6tfc^TFC9ijn(IJN This can be moved around the keyboard or expanded/amended for just about any level of security. This type of password also meets all the annoying requirements for 16 characters, uppercase, lowercase, symbols, and numbers.

Every few months, I switch up the pattern so all of my passwords change. It's a little tedious, but by remembering the pattern, I can right down password reminders that don't compromise my account. Using the above password example for a fictional account, I might write down this password reminder:

Yahoo email account: 6^9(

This tells me where to start the pattern, but not what the pattern is. Now, somebody may be able to guess that you just go down the keyboard with that simple example, so maybe your pattern could be something like this: 6ctf^CTF9nij(NIJ. Now the pattern has changed and it is mathematically just as hard to crack. The only limitation is your imagination.