Try combining three words, changing the uppercase and lowercase letters, and replacing letters with numbers or symbols. Let’s take the words "privacy and security" and look at the different passwords we can create:
privacyandsecurity
PrivacyandSecurity
Privacy&Security
Pr1vacy&Security
Pr1Vacy&Security
Pr1V@cy&Security
Pr1V@cy&$ecurity
Pri1V@cy@$3curity
Pri1V@cy&$3(urity
Pr1V@cy&$3(uRity
Pr1V@cy&$3(uR!ty
Pr1V@cy&$3(uR!+y
Write a note to yourself containing a hint to remember the three words, such as "what do I need to remember with my smartphone?" When you need to change passwords, choose three different words and go through the same process.