Med-Surg is notorious for acting as a filter course in nursing school because you can't just memorize your way through it. You have to understand the pathophysiology and immediately apply it to a clinical situation. The best way to study is to do as many practice questions as possible before the actual test. I highly recommend using a dedicated prep resource like https://www.simplytests.com/exams/nursing-school to test your knowledge. Working through realistic case studies and reading the detailed rationales for why an answer is correct trains your brain to prioritize care exactly the way your professors expect you to on exam day.