If for any reason you have to miss a class, it is a good idea to get copies of notes taken by other students. It's also a good idea to discuss the class content with your classmates to assure your confidence in the missed subject matter. Whenever there are discussions, projects, or labs, be an active and willing participate. The class will be more enjoyable and you will learn more. When you participate in class, you also show the instructor that you know the material.
Some instructors give points for class participation.
Make sure you read your course syllabus closely. Be a good group member. The number one reason people get fired from their jobs is because they can't get along with their co-workers. It is therefore not surprising that businesses and industries are encouraging educators to teach students how to work together in small groups. Do your share of the work and do it well.