Congrats on being back in school. What in the world do you do now? Prepare, prepare, and do it. Here’s how:
When I was an undergrad (and even now that I teach), I would buy an academic month-at-a-glance calendar. I use different colored pens for each class and mark off all of the assignments (including reading assignments) that I had for each class. One English class might be blue ink; another class would be green; still another was red or purple. (Write the number of the class in the same color ink next to the assignments or you will get hopelessly lost. You will, however, have a very colorful book!)
When there was a major assignment, I would highlight it with a yellow marker, to make it stand out. In fourteen years as a college student, I only forgot one assignment. I had forgotten to look at my calendar and was going off of my memory. Oops!
Keep that calendar with you at all times. Is this old-fashioned? Yes. Does it ever crash? No. Does it require that you charge it at night? No. It simply sits there and works.
I hope this helps!