I wrote previously about what makes a good mnemonic story for remembering kanji. Today I’ll add a couple more thoughts, which are obvious enough but sometimes easier to state than to follow.
Firstly: keep it short. A dozen words is okay. Eight is better, six is better yet. If you could find a way to make a sentence exclusively from keywords that would be the very best.
The problem with long stories is that at some point you have more detail than you need and it becomes harder to remember the story than the kanji. Even if you primarily rely on visual memory, a lengthy description of the event or situation contained in your mnemonic can cause more confusion than assistance. It’s easy and fun to get carried away and write a novel but that isn’t what we’re here for – do that later (in Japanese)!
The main intent of the mnemonic story is simply to string together the elements in a logical order. Don’t burden it with anything more than it needs.
Secondly: a strained story using the definition of the keyword that first pops into your head is far, far better than a polished and fluid story using a definition that you wouldn’t normally think of. The character for “shift” – 移 – had such a difficulty for me. The story I used had to do with the wheat (禾) field with its many (多) stalks of wheat “shifting” in the wind. Not the sense in which I’d usually take the word “shift” – I’d be more inclined to think of some ground shifting, or maybe shifting a transmission in a vehicle. I find that using such a story doesn’t really hurt short-term memory that much, but long-term won’t work as well. (I’m using this example because it just came up for the first time in a month or so and I forgot it.) So as tempting as it might be to use a nicely-crafted story based on a view of the keyword that you wouldn’t normally take, just resist it and make your own story using the definition you first think of, even if it’s a bit clumsy.