Postby boku1571 » January 12th, 2012 6:41 am
The best time, in my opinion, is WHILE you are learning the associated vocabulary. Reviewing each of the Kanji will reinforce the vocabulary that goes with it at the same time.
As far as readings, you should learn the two most common, one each of the ON and KUN readings, as that's what you'll encounter most. Once you've learned those two, you'll often be able to "sound out" new words by using those readings, and if it sounds like a word already in your vocabulary, then you've figured out another word. For instance, if you've learned 先 as "せん/ sen", then you can recognize it in both 先生 and 先週 where it actually has different meanings but the same readings. That is why learning the reading as well as the meaning is important. The time spent studying the kanji for both of those vocabulary isn't wasted on your speaking vocabulary either - you WILL learn the spoken word faster, and by the time you remember the Kanji, the pronunciation and meaning will have stuck in your head as well.
Personally, the method I use for studying Kanji are Anki decks. However I wasn't happy with many of the decks I could download, so I made my own decks that gave me the information and context that I wanted. The main idea though, is spaced repetition. You can use the flashcards too here on JPod101 if you're a premium member as well, the new flashcard tool is a great way to study both Kanji & Vocabulary at the same time.