Studying medicine is a exausting process and it needs a great discipline and sacrifice, but the most important thing is, take care of yourself, then you can help other people. You can have really bad consecuences for your healt if you adopt bad habits. Don't ruin your healt eating fast food, drinking a lot of coffee or avoiding exercise. Your body needs exersice and sleep. Your brain needs healthy food, water, fruits and vegetables. Don't compete with your classmates, this carreer is about competition, you fight for get one place in school, for good grades, for almost everything, but that don't make you better student or person.
Try to avoid everyone after an exam, you don't want to know what you failed after three days without sleeping! that's makes you want to commit suicide. You can't change anything, if you failed, try again and make it better, don't torture yourself with your own mistakes. Nobody is perfect, keep trying. You can study with friends, in my opinion it helps you a lot. Everybody learns in a different way, but you can share information and see things from another perspective.
Make practice questions while you study, you can read a thousand times the topic but try to understand what you are reading. Sometimes we just read but our mind is focus on another thing, That's a huge problem. You can answer for yourself, and by that I mean not outloaud, what your teacher is asking. It helps you to know if you're learning something or if you need study more.
Do what you like. If you used to like dancing before, then do it! Don't let the school eat all of your hobbies, you need them. Try to give you the time to do what you love. When you were in high school you had a life, maybe you used to run for an ice cream every wednesday, keep doing it but don't forget you have to study later. Make a schedule, so you can do more things in your day and make your day count.