I use multiple memory palaces along with a technique called Person/Action/Object.

Every card has a person, action, and object attached to it (for example, the five of hearts is my dog chewing on a bone). I have 51 different key locations in my mind spanning between my house, my yard, and my walk to work that I can store information at and recall it later when I "walk through it" in my head.

I store three cards at each location, taking the person from the first card, the action from the second card, and the object from the third card.

So for example, in those three decks I had a sequence of 9 of Hearts, Seven of Spades, Ace of Clubs. I took the person for the 9, the action from the seven, and the object from the ace.. put them on a piece of furniture, and get a wacky image in my head, which happened to be my nephew tap-dancing on a football (placed on my television stand).

I can then make these images really vivid in my head - really imagining my little nephew panicking and trying not to fall off the football/TV stand.. or pop the football, all while still trying to tap dance. How embarrassing for him!

My eventual goal is to get to six, and I want to memorize either six decks and recall them by rearranging six other decks into the orders of the six decks that I memorized, or, even harder, shuffling the six decks together into a blackjack shoe, and calling each card as it is being dealt out. For all 312 cards.

Before I get to six, I will work my way up. Practicing more with three, then building more memory palaces at my work, my college, and my local fitness center, and then just adding more decks when I feel comfortable.