Calculus Detection can be a super challenging skill to develop. It is much like any other detailed skill - it takes practice, persistence, and a commitment to the process. Listen to your professors when they say "roll around the line angle and lighten up your grasp." I know it can feel daunting, but these things actually work. In addition to those fundamentals, there are some othter tricks that may be helpful for you to know as you embark on your next clinical rotation.
Additional resources:
Study Sheets: https://thehappyflosserrdh.etsy.com/
Specialized Course: How to be successful in Dental Hygiene School
https://billie-lunt-s-school.teachable.com/p/how-to-be-successful-in-dental-hygiene-school