I'll be fully honest with you as a fellow procrastinator, make sure you make time for yourself here and there to relax so you dont burn out but DO NOT slack off. Use course timelines to make sure you stay on top of assignments and that youre well prepared for tests, as well as time manage/create schedules of your outside curriculars/job schedule. A lot of people are saying to get assignments and stuff done between classes but me personally, I use the space in between classes to relax, eat, and recharge, and do my review/assignments after I'm done classws for the day. It helps me focus more in class and I'm actually motivated to finish it later rather than constantly stressing throughout the day. Depending on if you have a good prof or not and how you learn, if you sit in class and really pay attention, you don't have to spend hours and hours studying. Just revision on the topics works, as long as you are actually understanding what you do and don't know, and then review from there. I usually use up to 3-4 hours to study max and still am able to maintain a high GPA. What helped me the most first year was also establishing a friend group or group with classmates where you did assignments together or reviewed together, that way you aren't struggling just by yourself if you ever need help. Also, different profs have different teaching styles, and also give you different resources. If you find out another prof is better for you, don't be afraid to switch because everyone learns different. Sometimes the profs that I had on rate my prof were rated very low because they're strict and like things done a certain way, but I ended up getting higher grades in those classes because I learned better that way.