Japanese is full of those characters originating from China. The trouble for most learners seems to be to remember their readings. There are numerous ways to memorize at least the 音読み. One of them is called the movie method, invented by a member over at kanji.koohi.com This is very helpful, but as you know, there are not only 音読み but also 訓読み readings. And once you are learning vocabulary, you will run into the problem, that words can have one and the same reading and you have to remember them.
One method to remember the readings of words written in Kanji is to look at the word, lets say 日本語, and remember it as that. But what if the same character has a number of readings, because it is used in other words containing that Kanji? This is, what seems to make the process more difficult, than it is. But how can you make the seemingly difficult problem of having to remember many readings for one Kanji almost as easy as learning your ABC’s? Impossible, you say? No! And here is the trick.
Lets say you want to learn 厚生. If you look at the kanji to the left of せい, can you spot a familiar part? Let me help you, it is 子. You know this one from words such as 子ども, right? In 厚生, however, it is pronounced こう, not こ alone as in 子ども. The trick is to connect the reading of a word you are trying to learn to one element of a Kanji, and not the kanji as a whole, to remember it. This is because one Kanji can still have numerous readings. In case of 厚 it can be あか、あつ、 あつ・い or コウ.
Lets examine another word containing the Kanji from before 厚着. This time the reading of the left Kanji is あつ. Can you think of any word which contains あつ as well? If you say 暑い as in hot reffering to weather, you have come up with the perfect word to connect this reading to one part of 厚, 日. 日 can mean day or sun, in this case think of sun, because it fits the word. What would you never do when it is hot? Wearing warm clothes, correct? So, once you connect あつ to 日 in the left Kanji for this word 厚着 you will never forget the reading for it. 厚着 is then easy to remember as being read as あつぎ which means wearing thick clothes.
The only problem is, that this trick doesn’t work with all Kanji. For instance that 明, which I think is a perfect example, for this problem. This Kanji can be read as あ・かす、 あか・らむ、 あ・かり、 あか・るい、 あか・るむ、 あき・らか、 あ・く、 あ・くる、 -あ・け、 あ・ける、 ミョウ、 ミン or メイ. And you can’t simply go and say I connect it with one of the two parts making up this Kanji. The only way is to remember it is in combination with the Kanji or ひらがな that precedes or follows it, 証明 [しょうめい], 明白 [めいはく] or 明王 [みょうおう].
Once you get used to connect readings to only parts of Kanji, you will have no problem to forget how to pronounce a word anymore. This trick should also help you to learn new words, and the readings for it, almost as easy as your ABC’s.