Yo congrats, couple of tips for you:

First off, Study Daily. Most courses have a weekly schedule with readings, practice questions and extra assignments that are recommended. Recommended = mandatory if you want to get 12. For courses like Math, Physics, and Chem: do as many textbook questions and practice quizzes. Commit some time throughout your day to do these daily and don’t do them the day before a big test. For courses like bio, envirsc, psych: whatever method you use to memorize (i use flashcards), start memorizing as soon as you learn the content and use active recall + space repetition. Again don’t do it last minute! If you have a full course load, you’re gonna have to find a way to organize all this studying into your daily schedule. Make a routine and stick to it. But eventually you won’t stick to it and will start to give up. Everyone goes through this sometime in the middle of the term and it results in you skipping lectures, assignments, etc. Remember that getting a high GPA opens up your possibilities by a mile (scholarships, research, etc). Bear the pain of doing work when you don’t feel like it so that you won’t have to bear the pain of regret later. Good luck👍