I recently borrowed a book called "Japanese Words and Their Uses" by Akira Miura.
It gives an in-depth look at 300 Japanese words that are commonly used incorrectly.
Here are some of them which I'm certainly glad to learn of:
AMAI
Unlike English "sweet", amai cannot mean "amiable" or "kind". In English, calling someone a sweet person would be complimentary. In Japanese, on the other hand, "amai hito", if it means anything at all, can only be interpreted as either "an indulgent person " or "an overly optimistic person".
NIHONJIN
"When "nihonjin" is written in Kanji, the last character is the one for "hito". Since "hito" is not an honorific expression, "ninhonjin" is not either. Upon meeting a Japanese-looking stranger, therefore, it is not courteous to use "Nihonjin desu ka?" to mean "Are you a Japanese?" It is better to ask "Nihon no kata desu ka?", using "kata", the honorific counterpart of "hito".
SOO DESU
"Soo desu"...and its negative counterpart, "Soo ja arimasen"...are most normally used in response to a question that ends with a noun + desu ka (or ja arimasen ka).
In response to a question that ends with an adjective + desu ka, or a verb + desu ka, don't use "soo desu" but repeat the same adjective or verb instead.
"Sore wa oishii desu ka?"
"Ee, oishii desu yo."
The above does not apply to "soo desu ne" or "soo desu ka?"
"Sore wa oishii desu ne."
"Soo desu ne."
That's all I can be bothered to type! Sorry!
The first edition was in 1983, with the third in 1990, so I expect everything is still relevant.