How I learn Japanese vocabulary quickly
When learning foreign languages, we often look for parts of the new word which remind us of a word in our native language. This often comes in the form of cognates with relatively closely related languages. For instance, the English, “magnificent” goes together obviously with the Spanish, “magnifico.”Learning words like this is ridiculously easy. But what do we do when learning languages that aren’t related to our native language at all and thus have no cognates?
Find less obvious connections.
Let us take for example the Japanese word, 「かさねる」 “kasaneru,” which means to “stack; pile; repeat.” At first this looks like a challenge but as a native English speaker, we all know the Spanish word “casa” meaning house/home. This is found in the common expression “Mi casa es su casa,” or “My home is your home.”
All of a sudden, your mind has an anchor point on which to learn the meaning of the Japanese verb. For instance, you can think of “casas” or houses stacked on top of each other which is quite an odd image. Also if you know that “neru” means “to sleep” in Japanese, you can add that easily to your mental imagery to create houses sleeping upon one another. Quite quickly the word “kasaneru” becomes associated with “stacking” in your mind.
One more example of a word I learned just last week. 「たずねる」 “tazuneru,” which means “to ask, inquire, investigate.” This one was kind of tough but I eventually came up with using a mental image of the Tasmanian Devil spinning through a stack of papers investigating something.
These mnemonic devices are only to help you get the word initially into your head. Eventually the mnemonic device will fade into the ether and you’ll just know the word like any other word you know fluently. Also, the larger vocabulary in your native language or another language you have, the easier it will be for to come up with creative ways to remember the vocabulary of your new target language.
Please leave a comment with any mnemonic devices you’ve come up with to remember certain words.

This may be because I’m still doing Heisig, but I find it much easier to learn a new vocab word if it has kanji in it. If I have problems with remembering its reading, I try to incorporate it in the story for the given kanji.