They emphasize discussion and presentations by the students. In American universities, students' evaluations are counted for their promotions. Teachers have office hours for two to four hours a week, and students can see them at their office easily. They show a willingness to see students and help them. They are supposed to help students, and that is part of their jobs, and part of their evaluation from their students depends on the availability to students.
Exams are more important in basic courses.
They cover everything taught in the class, plus reading done outside of class. Students have to study hard to understand everything, memorise important information, and apply the theories that they have learned. In seminars, which are more advanced and for fewer students, exams are not emphasised, but individual research, presentations in class, and writing papers are emphasized. Many courses have two tests, a paper, and other projects, and teachers have to grade all of them. In the third term and during the summer, students spend most of their time writing their dissertations.