Actually there are quite a few apps for memorisation using flash cards and space repetition out there, I chose Anki app because I am quite lazy in creating cards myself and I like this simply because I found a good shared deck haha. I like this deck because many of the decks created do not have Hanja, and this one does. And it contains vocabulary from low to advanced level, however, if you find some of the words too easy or too difficult, you can simply suspend them, and they will not appear when you are studying.
我最近用的，也上面我推薦的就是Korean Vocabulary by Evita。因為我拼字也很有問題，所以臨近考試前幾個月，就由初級的開始，但是反轉那些生字卡，出現的答案，然後我默韓文。
It is quite a convenient app with computer and phone version, you can add cards easily when you are at home or study when you have time during commute.
The deck I mentioned above is Korean Vocabulary by Evita. Because my Korean spelling is not that good, and TOPIK is coming in a few months, I started studying from the beginning but with the cards reversed so I can practise my spelliing.