There are ways of creating memorable random passwords.
Take a random phrase and a random but memorable number such as a telephone number you know.
Use the first letter of each word in the phrase and intersperse the letters with the numbers also alternate between capital and ordinary letters and you end up with a secure password.
So 'Mary had a little lamb' and 12345 would become either m1H2a3L4l5 or M1h2A3l4L5 for example.
Pick a phrase that no one would guess is a password reminder such as 'I must remember to call Fred Bloggs about blah blah blah on 1234567' and write this down as your reminder.
If anyone sees it they'll not suspect it's a password reminder and you'll have it there if you ever forget.