We can learn from the practice of experienced colleagues. A seating chart enables the instructor to check attendance and call students by name. A student is more likely to attend class if he knows that the professor is aware of his absence. There are other practices that we can emulate. An information card on which the student writes about herself helps establish personal impressions.
Some instructors take mug shots of students to learn faces and names.
Walley Cordes has a 3-minute interview with each of some 200 students near the beginning of the semester. It takes most of a week but results in his getting to know all his students. Studies suggest that learning is enhanced when students feel that the faculty knows them, and certainly the instructor gets higher student evaluations. Even though some active learning techniques used in small classes may not be suitable for large classes, there are a multitude of active learning exercises that are. Lectures may be interrupted by one on one interaction between students.