It's midterm season once again and now that I am a senior, I should have more expertise in this subject. But to be honest, midterm seasons at CAL are some of the most difficult times to weather through. And I still have trouble myself with achieving that perfect balance, but I do have some advice from my experience to share with you. I feel that the most important thing is to start early. No matter what, review the notes from your classes that day and rewrite a few things that you were unclear on. Jot down your questions and go to office hours!! This way, you will keep up with the material and rest assured that your understanding of the concepts are thorough and complete. The additional interaction with the professors may also open new opportunites for you. This applies to both before and after your midterms: Review the information you did not understand and go to office hours for further clarification.
You may find additional pointers from my midterm blog post last semester.