One thing that you might want to be careful about when learning Japanese with anime is that the characters often use very casual expressions. It is fine to use those expressions with your family and friends, but they are not appropriate to use to your seniors or in formal situations.
One of the reasons I wanted to learn English was to be able to understand English (Hollywood) movies, without the need of subtitles. It is a fun way to learn Japanese if you enjoy watching Japanese films. Japanese animated films are also enjoyable.
J-pop (Japanese pop) refers to Western influenced Japanese popular music. Enka is traditional Japanese ballads. J-pop seems to becoming popular these days even outside of Japan.
Japanese children’s books are called "ehon." There are many great "ehon" available in Japan. Also, I found the cost of hard cover books to be quite reasonable when compared with North American prices.
Since many children's books are written in hiragana only, they are very useful for beginners to practice Japanese writing with. I like the "EhonNavi" site to search for children’s books, though it is in Japanese.
You have learned some Japanese, but haven’t had chance to try it out? Find Japanese pen pals and exchange your language and culture.
My favorite site for kids to learn Japanese is "Kids Web Japan." There is lots of information about culture and history, and some Japanese lessons. It features animation, games, etc. It is great material for adults, too!
Learn while you play.
They are effective ways to memorize vocabulary, kanji etc.