I use flashcards to memorize things. Sometimes I use mnemonics to memorize flashcards. I used memory palace once, to memorize something for a Romanian language exam back in highschool.
Things that I memorize now: Bible verses (I've memorized all of Galatians and I'm working through Ephesians right now), a couple of important phone numbers, credit card number (I don't want to save the details on every website), and some programming concepts that I use on a roughly monthly basis - frequently enough to save time by memorizing, infrequently enough so that I can't memorize them purely by using them.
Things that I memorize now: Bible verses (I've memorized all of Galatians and I'm working through Ephesians right now), a couple of important phone numbers, credit card number (I don't want to save the details on every website), and some programming concepts that I use on a roughly monthly basis - frequently enough to save time by memorizing, infrequently enough so that I can't memorize them purely by using them.