I noticed once that I always spelled the word "receive" wrong - this was back in the late 1990's. The problem, of course, is that tricky "i before e" rule. Our school's server required us to change the password every three months, so I decided at that point that I would change it to a combination of the word receive and some numbers (the school server also required numbers in the password).
Ever since then, there are times when I find I spell words wrong, and in order to fix that, I will make a password the correct spelling of that word. It kind of serves two purposes - one, I will remember it - I am usually aware of words I spell wrong - and two, I end up getting in the habit of spelling the word properly.
On accounts where I have to change my password every few months, I still to this day stick to this, and have retrained myself to correctly spell receive, judgment, and many other words that I would otherwise type wrong the first time.
I know it's a silly little thing, but it has helped improve my spelling a bit, and it's certainly a better choice of password than something easily guessable, like something to do with my family, or profession, or something else of that nature.