I used the Hello Chinese App (https://play.google.com/store/apps/details?id=com.hellochinese) to learn vocab, reading writing. Its got a good way to learn the words, review, and it really helps you be fluid in your thinking when using the language.
Otherwise, hellochat is perfect for practice. I used these for 6 months before coming to china, and after that is was so easy to keep picking up the language organically.
Also pleco for looking up characters and stroke order.