This is NOT an exhaustive list of PA prerequisites as each school is different. For more specific info, check the websites of the PA programs you are planning to apply to.
General biology - Take notes during class, create Quizlets with key terms/concepts
General Chemistry - Notes during class, Quizlets for key terms/concepts, utilize any office hours with professor/assistant, create practice problems for each chapter, and complete any homework offered by the professor (redo the problems and write down what specifically you're having trouble with and bring it to office hours or ask a classmate).
Microbiology - Notes during class, Quizlets for key terms/concepts, create study guides to understand the key processes (Ex. Krebs cycle, ETS, Anaerobic respiration, ATP synthase, etc.)
Immunology - Similar to microbiology. Key processes: T/B cell activation from start to finish, immunological response (differences between each), etc. (Refer to syllabus "course goals" section).
Organic chemistry - Similar to general chemistry but make sure to create flashcards for your functional groups (KNOW THESE BY HEART). Make flashcards/charts with reagents and what they do in a reaction.
Anatomy/Physiology - Notes during class, flashcards for anatomical structures, go to ALL lab times, and also outside of class time! Looking at the actual 3D structures is huge to understanding the musculoskeletal, vascular, and neurological especially. Quizlet for key terms/concepts. Invest in a paid (or free) anatomy app that you can reference or study when needed. Use all the tools available to you!
*Some programs also may require physics, medical terminology, etc. You can use similar methods for these as outlined above*
*This list does not include prerequisites for your undergraduate major, typically English, language, calculus, statistics, etc.*