Time management is a very important factor to academic success. As you plan your schedule, remember to keep in mind time needed for class preparation, tests, papers, and projects. It's recommended for every hour you spend in class that you devote at least two hours to studying. For example, if you take 12 credits, you should plan to devote 24 hours toward studying outside of the classroom. So time spent dedicated to school each week can equal up to 36 hours, essentially a full-time job.
You should also take into consideration your no-school responsibilities, such as family, work, and other personal commitments.