Schedule in Breaks
Make sure to schedule in breaks during your day to make sure you have time to decompress. Especially make sure to leave some time for lunch.
Harder Days at Start of Week
Try to schedule harder classes or longer days at the beginning of the week, as this is the time you will feel most refreshed and productive after the weekend.
Group together similar activities in your schedule. For example, try to leave larger breaks to leave enough time to thoroughly complete homework. It is a lot easier to enter "deep think" and complete work in a three hour period, rather than have three hours broken up by class. Your brain has to switch contexts too much.
Mix of Subjects
Try to include a humanities or social science class every term to balance out the rest of the STEM classes.
Ask for Help
Reach out to your advisors or older peer mentors for scheduling advice! People here want to help you and are more than willing to answer your questions.