Finding the key is step one. Using it correctly is where the magic happens. Most students check their answers, see they got 60%, and move on. That is a mistake.
Here is the 5-Step Method used by top-scoring students: Finding the key is step one
Many students save answer keys to public Google Drives. Search: "Oxford Advanced Set 6" site:drive
"Oxford Advanced Set 6" site:drive.google.com Get the oxford advanced hkdse practice papers set
Get the oxford advanced hkdse practice papers set 6 answer key (the best version you found on Google). Mark your work with a red pen. Be strict. If you were 50% correct but gave yourself credit for a vague answer, deduct the point.