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.
If you are totally stuck, look at the solution, but only look at the first step.
Since the 7th edition is an older staple, there are now incredible visual simulations (like PhET or YouTube walkthroughs) that map directly to Serway’s problem types.
Many students find the problem sets in the 7th edition to be more logically sequenced than later versions. The solutions manual reflects this by categorizing problems into: Testing your intuition. Worked-out Examples: Step-by-step guidance.