> I still haven't memorized all hiragana and barely none of katakana...

I warmly recommend James Heisig's books Remembering the Hiragana and Remembering the Katakana. They claim to teach you each syllabary in three hours, and they do not lie about this. Me and several friends have all used these to very quickly and efficiently learn hiragana and katakana.

There's a combined version too; http://www.amazon.com/exec/obidos/tg/detail/-/4889960724/002-0281214-3618431?v=glance