Once the goals have been determined, materials and activities that will be relevant to the goals should be selected . For example, a student wants to learn English so that he or she can work towards a GED, the materials that are chosen should provide vocabulary and language patterns that are used in basic secondary textbooks.
Students will be further motivated if you remind them how each of the activities that you are doing will help them move towards their goals (e.g., "We're doing this activity so that when you are taking a math class, you will be able to . . .").
One of the most important factors that motivate students is a sense of progress. There should be clear markers of success so that students can look at what they are doing well. This means that there should be fairly frequent measurements (questioning individual students, short quizzes, corrected homework, etc.). Too often teachers avoid measurements because they are time consuming or because the students have an inordinate fear of examinations. However, a wise teacher will build in easy, convenient ways of showing the students their progress. One simple way of doing this is a simple checklist of tasks that the students would want to be able to accomplish in order to reach their overall goal. As they do the tasks one by one, they sense their progress and feel that the class is worthwhile. This will keep them coming until they reach their major goal.
A second factor that will maintain and increase motivation for your students is enjoyment. Activities should provide opportunities for real social interaction and getting to know other people in a relaxed and, sometimes, even humorous ways. If activities are exciting enough, students will not want to miss class because they know they will be missing the "action." If you help your students develop feelings of respect and friendship for one another, those ties will also draw them back to the class.
Relevance is probably the most important motivating factor for adult students. If the students are exposed to and study life-coping skills, e.g. balancing a checkbook, applying for a job, etc., their interest will never waiver.