The most effective way to learn to read and write in German is to practice the language with foreign speakers. People unable to relocate to Germany, however, may attend classes at the Goethe Institut or use a German language app such as Duolingo.
The Goethe Institut is an internationally recognized language school that offers a variety of German Courses and provides students with certificates immediately upon completion. All students are required to take a placement test before enrolling in classes.
Duolingo is an app that can be used as a tool to learn several different languages, including German. Users may practice their reading and writing skills, as well as complete grammar exercises. The app is free, as of January 2016.