Attend you classes regualry ( eng exam's essay ) I think, presence at the lessons is very important. There's a few reasons. First of all, you will not skip any valuable information about the subject you study, about the university life, exams and etc. Second reason is that you'd better be involved in study process , answer teachers questions, do exercise during classes. Teachers should know what kind of student you are, are you interested in your major or not, what's you future plans. All these things are connected with attendance. Moreover, when time of exams will come, for you won't be that difficult to prepare. Because you are alredy familiar with the discipline, you've been doing everything very well, so you just need to revise all materials and that's enough. Life of students full of stress and tension, but if you will come to classes in time and do things which you need to do, then process of getting knowledges will be more efficient and easy at the same time.