Ask the instructor if you can tape the class if that is your style. You may wish to get tutoring help from other students. It is also a good idea to develop some memory strategies such as review, rehearse, associate or organize. Time management is always a key. If you are a working adult or have family obligations, it becomes crucial to manage your time carefully.
Some students treat school like a job and spend the appropriate amount of time.
Others like to be active in many different parts of life and can concentrate better that way.