Consider becoming certified as a German teacher or training as a teacher with a short program. Not only will this experience help you find jobs, but the training will also provide you with classroom materials and strategies for students of all ages. Some programs, such as those offered by the Goethe Institute, focus on learners of all ages; however, you can also find training for teaching German to K-12 through degree programs such as a master's degree in education, offered at a wide number of universities around the country. The Goethe Institute offers classes in the United States, in Germany and online, as well as summer programs at a variety of institutions around the U.S. If you are a native speaker who has never taught before, training as a German teacher can help you learn to break down your language in a way that is understandable to non-native speakers.
Evaluate the level of your group. Once you have a group of adults with whom you are working, carefully evaluate their levels with a placement test or by talking to each person individually. Even in a beginner class, you may have "false beginners" who studied the language years ago and just want a refresher. By knowing where your students are starting out, you can come up with goals and corresponding lesson plans for the course.
Construct a lesson plan. You may need to construct a lesson plan that works for students of several different levels; for example, by giving more advanced students difficult vocabulary to work with for certain exercises. This lesson plan should include a variety of activities, and should allow for as much student-generated activities as possible; that is, the students should be speaking and writing as much as possible.
Work on all four language skills with your students. Focus on reading, listening, speaking and writing. Because German has complex grammar rules, it can be especially difficult for non-native speakers to generate correct sentences, particularly at the beginner level. Though students may wish to spend most of their time reading and listening, giving even attention to each area will help them learn German more thoroughly.