When I studied kanji, I learned how to read it but I think I didn't really pay attention to on and kun.. I am really sorry for my poor answer.. But on and kun are ways to read kanji, and the difference between them is that on is based on Chinese reading (pronunciation?) and kun is based on Japanese reading. Okurigana For example, this → 早く is read "hayaku" and the kanji "早" can be read "sou (this is on reading)" or "haya (kun reading)," but I know I should read it "haya (kun reading)" because of the okurigana "く" and "hayaku" means "soon." If I read it "souku," it doesn't mean anything. So okurigana tells you whether you should use kun reading or on reading.. I'm sorry, I wish I could explain this better.. I found a webiste (http://www.kanjisite.com/html/start/jlpt/2/all/index.html) and I think it may help you.. :) (They write on reading in capital letters, kun reading in lower-case (uncapitalized?) letters. For example, if you click the kanji 引 on the Batch 1/30 webpage, you will see "IN / hi(ku) / hi(keru)" written next to the kanji. IN = on reading, hi = kun reading)

1. When you study kanji, learn them by words. For example, suppose you want to learn 大. It's not efficient to memorize mechanically like "kun reading is 'oo' and on readings are 'dai, tai'...."　Isn't it boring? Instead, I recommend you learn words such as "大きい（おおきい）" ,"大人（おとな）", "大学（だいがく）" . In this way, you don't really need to even care about if it's on or kun. (That's what Takako means in her first line, I think.) When Japanese pupils take kanji test, it looks like this: Q. Write the underlined kanji in hiragana. "わたしの家は　大きいです。" 　　　　　　　　ー A.　　　　　　（おお） 2. You may come across with unfamiliar words written in kanji, and need to know how to read it. Here are some hints. -If it comes with okurigana, it's most likely kun reading. -Kun reading makes sense as a word by a single kanji itself or with okurigana if any. Most on reading doesn't make sense by itself. -It the word is made of two or more kanjis in row, it's likely to be on reading by 70-80% possibility. -To be 100% sure, get a electric dictionary, go to some kanji website, or use IME on PC that allow you to input by pen/mouse writing. It will give you the answer. 大きい→大is alone with okurigana. So it's おおきい。 大学、大統領、公明正大→Two or more kanjis in row. So they are probably on reading. And yes, they are. だいがく、だいとうりょう、こうめいせいだい。 大空→Two kanjis in row, but this one goes into the minor 20%. It's おおぞら. 大家→Could be kun(おおや) or on(たいか) depending on the context. You really need to know the meanings first. May need to look up dictionaries to make sure. *Okurigana 大きい→きい is okurigana. 白い→いis okurigana. 食べる→べる is okurigana. 飲んだ→んだ　is okurigana. Note that する for verb, な, だ／です for nouns and na-adjectives, and their variations are not counted as okurigana for this purpose. For example, 元気な looks like it has okurigana, but it's read by on reading げんきな.

hello, learning Kanji is not that simple as I can write all in this space, But there are some efficient ways. Let me know if you are interested in. I can give you some good links.

im not the first answering also im a beginer in japanese but i know that KUN reading is how you speak the word out also it means the thing the kanji means and ON is how u write or say the word when it is combined with another kanji like sui -ka(watermellon) or mizu (water) both the same kanji but the reading is different. I think the best way to remember is to remember the kun word first and then to remember the on using a two kanji word like i did.

The best I can recommend: Heisig: Remembering the Kanji. (A guide to remembering how to write them) Heisig: Remembering the Kanji 2 (A guide to remembering their readings) There is no quick way to this. Heisig's is the fastest though. Give yourself a few months! The Japanese learn their Kanji at school over a period of six years.