I've found a great way for making many complex but easily remembered passwords is creating a simple process.
For example:
Take your user name and make your password 1 letter after.
Username: abcd
Password: bcde
Username: MyUserName01
Password: nzvtfsobnf12
This way your passwords are all different and not at all easy to guess or dictonary attack.
A problem with this might arise if you use the same username for everything. In which case another simple step could be added to prevent the passwords from being the same.
By adding the name of the site after the password for example.
Username: abcd
Password: bcdeyahoo
Username: MyUserName
Password: nzvtfsobnfslashdot