The biggest mistake students make is treating a solution manual as a crutch. To get a better grade, you must change how you interact with the solutions.
Great solutions clearly define what the symbols mean. Is $v$ the initial velocity or final velocity? Is the mass $m$ or $M$? Serway’s problems often involve two objects (like a sliding block and a rolling cylinder). A better solution distinguishes these variables clearly before plugging in numbers. serway physics 7th edition solutions better