It's the start of a new semester. To start it off right, there are some things you can do.
First of all, breathe. You got this.
To start off on the right foot, the best thing you can do for yourself is to stay organized. As soon as you get your syllabi make sure you highlight all of the important dates: tests, quizzes, papers, and assignments. I find it best to keep ONE collective calendar for all my classes so I can easily stay on top of due dates. Keep in mind, things can (and most likely will) overlap. So it's best to know weeks (if not months) beforehand. I also like to make deadlines of my own so I'm not left scampering to the finish line to get assignments done.
The second thing that you can do to help yourself is to stay on top, and if possible, ahead of lectures. You'll find that some topics will come easier to you and others will attempt to get the best of you. If you fall behind, it'll be hard to catch up and you'll find yourself falling behind.
Once again, THE SYLLABUS IS YOUR FRIEND.
You should study up on the topic before the lecture, so you know what concepts trouble you. I also like taking notes on a topic before class and I jot down new tips/details during lecture. I find that this is more effective in forming a study guide later on. You can also form study groups for certain classes, although do try to keep the number of people involved to the bare minimum to ensure that you stay on task. Like I said before, certain topics will be a breeze while others will stump you. That's the benefit of a study group: to build upon the things you don't know and to strengthen the concepts you have extensive knowledge of.
DO NOT PULL AN ALL-NIGHTER TO CRAM FOR A TEST THE NIGHT BEFORE.
I can't stress that enough. What usually ends up happening in that scenario is that you barely remember anything the next day and end up giving yourself unnecessary anxiety.
What you can do the night before a test is practice problems and recite important key points.
Know when to say no. There are so many things that occur on campus. New jobs, internships, etc. Even your friends keep texting you to hang out. But stop.
You can't commit to everything at once.
It's best to keep things at a point where you're not feeling overwhelmed. A new internship sounds amazing, but you need to decide if you'll still be able to stay dedicated to your school work. That should always be a priority.
I also like keeping my phone on "Airplane Mode" or "Do Not Disturb." It helps me make the most out of the day. I noticed that keeping my phone in my bag while I'm studying is also very useful. I don't find myself scrolling through my e-mails every 10 seconds. Plus, you can even dedicate a time of the day when you reply back to the important emails/ texts.
Lastly, breathe again.
Utilizing your time and fashioning it in such a way that you don't get burnout in the first few weeks is vital. So know when you've had enough. If you're studying and you find yourself reading the same sentence over and over and over and over again- STOP.
Take a break. And come back. Don't keep forcing your brain. Chances are you'll end up overwriting the things you do know with nonsense. Let things sink in before you move on.