Basically an ABC-challenge but in Japanese, so read a book whos title starts with あ, then one that starts with い, then う, え, お, and then か, き, く, け, こ and so on, going through all the syllables of the 五十音. Any format and reading material is accepted; books, manga, childrens books, picture books, audio books, as long as it is in Japanese and the title starts with the right syllable. The title can start with hiragana, katakana, or kanji, and dakuten/handakuten is also ok, so for example, for た the title could start with た,だ,タ or ダ, or kanji such as 田中(tanaka) or 騙す(damasu). For を and ん, any title containing the sound is accepted, it does not have to be the first syllable. Good luck, enjoy your reading, and がんばります！