An easy way to have a long password is to use a phrase or sentence, e.g.
MyMothersnameisMary

If you need numbers in there, simply replacing O and I with 0 and 1 would suffice
MyM0thersname1sMary

Other examples
MywifeAnnewasbornin1970
Mylastaddresswas12TheHighStreet

These are ridiculously long passwords that are very easy to remember. The problem for most people is that they don't want to use a different password for every site. Passwords managers are all well and good, but if you don't backup often and lose the information, you are often severely inconvenienced. I work in IT and get bored of telling people how important it is to backup, especially when I am asked to recover all that really important data which was so important they never quite got around to making a copy anywhere. Sigh.