Having complex and unique passwords on every website without writing them down or forgetting them is impossible unless you have the right technique.
The following trick was the simplest and most useful security trick I ever learned regarding password security.
The solution is having a phrase which you remember and adapt to for each page. This can be anything, literally anything
E.g. the phrase "Every morning I make coffee and browse website X"
Then take always the first letter (and last letter) of the website's name, add hashtags and a number code like your birthyear etc., e voila:
'#EmImcabwX123#'
This password will get you a 'super strong password' award on every website you register - plus it is unique for every website. Especially when you not just use the first, but also the last letter of the website's name.
Try it, hope this helps you all!