generally, sleep before class. There are some occasions anda just can't stay awake but there is really nothing anda can do no matter how hard anda try...
Try having some coffee before the boring class commences. anda will not only drive away the sleep but also remain alert and ask pertanyaan and actively participate in the classroom to ensure that anda are on puncak, atas of your attention. If it's not possible to have coffee before the class, then, take a quick break to the kamar kecil, kamar mandi and splash some water on your face and have a chewing gum and return to the class. Sit up straight, feet planted flat on the floor. Don't lean back atau slouch in the seat,don't rest your chin on your hands, etc. If you're in a posture that discourages sleeping, it will be easier to stay awake. Try and focus on the lecture. Take notes. Maybe skim a little ahead in your textbook so anda have an idea of what the lecture will be on. Listen for key words atau ideas anda saw in the reading..