Consider the long term. Your uni work will take you roughly half a decade to get through, maybe a little less if you hustle. Your career will last roughly half a century, maybe more if human life spans continue to increase. Take advantage of your uni time to explore as many parts of the world of thought as you possibly can. Take risks. After you leave uni, noboby will care that you got somewhat low marks in that strange particle-physics (or whatever) class you signed up for.
This sounds trite, but it isn't: learn to learn. If you work in our trade (or any knowledge-based trade) you'll be learning for your entire life. You'll choose your jobs and assignments based on how much you can learn from them. Build your skills at extracting value from books and deciding which parts of them deserve a lot of your time and which don't.
One of the best ways to learn is to teach. Think of every assignment and problem set as an opportunity to teach somebody something. Every bit of work you do is an opportunity to teach. By "work" I mean creating things like documents, drawings, code, and so forth. Get in the habit of making things that are, at least potentially, useful to other people and to your future self. And when you gain enough knowledge in particular things, seek out opportunities to explain them to other people. Surround yourself with people who have the same attitude.
Get in the habit of prioritizing your work. You'll always have more to do than you can finish, so learn what to blow off. At the beginning of every uni term, take time to go through the schedules and syllabi for your classes and projects. Start by extracting the due dates for projects and putting them into a to-do list that works for you. Use a calendar app, or an electronic to-do list, or even a sheet of paper you can stick to a wall. That will get you started on planning and prioritizing. And, it will help you avoid nasty surprises like "oh no, I have a final exam in differential equations on the same day my project is due. And that day is tomorrow!!!"
Friendships and romances? Of course. Sex, drugs, rock-n-roll? Of course. Clubs, adventures, sports? Of course. Have fun. I joined a cycling club where we learned together how to work on bikes and took epic trips. But don't waste your uni years by overdoing those sorts of things.
All the best to you!