If by scoring good marks the question means scoring good test scores, yes, I believe education is important. Study habits are important too. Teachers are critical, though, and I do believe in merit-based pay for teachers. I believe those who produce the best methods for teaching and the best test results from students should be paid accordingly.
Motivation is very important for scoring good marks. I believe if an individual is motivated enough and interested enough in receiving good marks they will do just about anything to score well, even if they didn't have a very good education. It all comes down to a personal thirst for information and knowledge.