Obviously you want a medical school that has a great reputation, one that scores high on medical school ranking and is known to produce quality doctors. But there is much more to a school than just reputation. Know what kind of medicine you want to practice and find out if the schools you are considering have a reputation for quality education in that kind of medicine. Are you more interested in medical research or direct care of patients? You need a school that has a similar philosophy. If you are not happy at a school or it is not providing you what you need, it will be very difficult for you to complete the program in a reasonable amount of time, if at all.