The busier you get, the more stuff you forget, and navigating that mental clutter can be worse than steering through an asteroid field. Luckily, lots of intrepid galactic heroes have faced faulty memories, and created some handy techniques for remembering.
Here's a complete list of all the methods we found for jogging your memory from science fiction tales, from the least fantastical to the most. (The end of the list, sadly, includes some items that you're unlikely to be able to find at your local office supply store.)
Use an acronym.
Suppose you've got a beautiful blue time machine that goes by the ungainly name of Time And Relative Dimensions In Space — you can always shorten it down to TARDIS, which is much easier to remember. That's what the Doctor (and his granddaughter Susan) did in Doctor Who.
The same goes for Marvel Comics' super-secret spy organization, the Supreme Headquarters, International Espionage, Law-Enforcement Division (S.H.I.E.L.D.) The only problem with acronyms is, people will change what they stand for when you're not looking — S.H.I.E.L.D. now stands for Strategic Hazard Intervention, Espionage Logistics Directorate in the comics, or Strategic Homeland Intervention, Enforcement and Logistics Division in the movies.
There's also the General Unilateral Neuro-link Dispersive Autonomic Maneuver (GUNDAM), and lots of other examples, here.
Write yourself a post-it note.
This may be the most foolproof method out there. In Star Trek: Voyager, Chakotay falls in love with a member of a species that erases itself from your memory after a while — and also somehow deletes all computer records. To guard his memories of their torrid, torrid love affair, Chakotay writes himself a paper note explaining everything that went on.
Similarly, in Scott Westerfeld's novel Uglies, Tally Youngblood undergoes the surgery to become a Pretty — but first she writes herself a note explaining all the plans she made to reverse the surgery. Because she won't remember them after she's become a Pretty.
In the movie Push, Nick gets someone to erase his memories and the memories of all his friends, so the mind-readers can't follow their plans. But he writes letters for himself and everybody else, to help them remember at the crucial moment — and there are instructions on how long to wait before reopening the letters.
And this technique is also used by Gwen Cooper in Torchwood (with so-so results), Noah Bennet on Heroes and Kurt on Odyssey Five. There's a great list over at TVTropes.
Keep a diary:
This is one step further than just writing a little note to yourself. In Gene Wolfe's novels Soldier in the Mist/Soldier of Arete, the protagonist loses his memory every single day. And he doesn't realize that his ability to converse with gods, ghosts and other mythic figures is unusual. He writes himself a detailed diary, and the first line of it is, "READ THIS EACH MORNING."
Lost's Daniel Faraday keeps a diary too, and seems to use it to remind himself of a lot of stuff he's forgotten as a result of some time-travel experiments that went wrong. Among other things, he doesn't remember writing the stuff about Desmond Hume being his constant.
Make up a song:
That's what Draycos does in Timothy Zahn's novel Dragon And Thief: A Dragonback Adventure. Draycos sees Jack being taken away on a spaceship, and needs to remember the words written on the ship's side — but they're in English, a language Draycos doesn't know. Says Draycos, "Alien symbols are difficult for one unfamiliar with them to memorize. But I am a poet-warrior of the K'da, and so as you were taken aboard the ship, I composed a song." For example, to describe the letter A, his lyric goes, "Two soldiers lean to, with joined hands." Or to describe the letter O, he sings, "Squeezed ring of fire, and what is more/A fire burns within its core." If you have an easier time remembering goofy song lyrics than unfamiliar symbols, this could work for you.
Leave yourself some objects to trigger a memory:
In Paycheck, Ben Affleck sees his own future, but then has his memory erased. So he leaves himself an envelope full of tiny objects, including a nail and an old penny, and a lottery ticket. They mean nothing to him — until he realizes that they're each incredibly useful at just the right moment. And they do help jog his memory, sort of. The Doctor on Doctor Who is constantly tying a knot in his hanky to remind him of things — but then he has to leave another knot in his hanky to help him remember why he made the previous knot.
Make yourself a video:
That's what Arnold Schwarzenegger does in Total Recall — he's forgotten his true identity as an agent of Mars intelligence (or maybe there was never anything to forget?) And now he leaves himself a video to explain everything — except maybe his past sellf isn't quite telling the exact truth.
Rodney McKay also leaves himself a video message in Stargate Atlantis after everybody loses their memories in the episode "Tabula Rasa." He tells himself to find Teyla quickly, or hundreds of people are going to die.
Create a memory key or "memory palace":
This one is a bit more involved. In John Crowley's modern fantasy novels, the Aegypt tetralogy, we meet the real-life philosopher Giordano Bruno, who had created a complex occult memory system, based on assigning graphical images to different pieces of information, allowing you to access them easily later. One such scheme involved concentric circles, and could allow you to set aside tons and tons of information. The Aegypt novels include the adventures of Bruno, who becomes the librarian of the Secret Library of San Domenico, keeping track of the huge collection of heretical texts using his amazing memory powers:
He knew and remembered every book, where it lay in Fra' Benedetto's cases, who had asked for it, and what was in it. In his vast and growing memory palace, the whole heavens in small, all that took up next to no room at all.
Also, in Orson Scott Card's Intergalactic Medicine Show, Tzu creates a "toy cupboard" in his mind, among other techniques for creating an order for random facts:
He learned to memorize longer and longer lists of things by putting them inside a toy cupboard the tutor told him to create in his mind, or by mentally stacking them on top of each other, or putting them inside each other. This was fun for a while, though pretty soon he got sick of having all kinds of meaningless lists memorized. It wasn't funny after a while to have the ball come out of the fish which came out of the tree which came out of the car which came out of the briefcase, but he couldn't get it out of his memory.
The Mentats, or human computers, in Frank Herbert's Dune seem to use a variety of techniques, including memory keys (and sapho juice) to remember tons of information with perfect clarity. There's a Yahoo group where would-be Mentats have posted advice on how to train your mind to be as clear as that of a Mentat — or a Vulcan.
It works for the guy in Memento.
Take smart drugs:
It's pretty amazing what you can do with smart drugs, but in Woody Allen's story "Think Hard, It'll Come Back To You," a smart drug called Cranial Pops can help you recall any weird bit of information that may have gotten away from anyone, allowing you to be the hit of a party — until they wear off and you crash.