There are many qualities that a good college student needs to have.
First, a good student needs intelligence. College classes are not easy. Students need to have the brain power to do well in them. Brain power is not a guarantee that a student will be a good student in college, but it is a very important factor in success.
Second, a good student must have self-discipline. There are a tremendous number of distractions available in the college setting. Students must have the ability to block those distractions out well enough to succeed. They do not have anyone else to rely on to make them study. Therefore, they need self-discipline.
Third, a student needs to be motivated. There are plenty of smart people who do not do well in college. In many cases, it is because they simply do not care enough to put in the work that is necessary in order to succeed.
Thus, what we can see is that students need intelligence, but they also need other attributes. They need to have the desire and the discipline to translate intelligence into success.