For improvement, it’s best to tutor both weak and strong students

In your early stages as a tutor, it’s good to tutor a range of students in ability. Each ability group has its pros and cons. Tutoring weak students can be more work but it forces you to really learn how to break down the concepts and learn different ways in explaining.

If you only tutor strong students you will take some of your tutoring habits for granted that may not work with a sizeable number of weaker students.

The pros of tutoring strong students is that they really push you in the knowledge domain and force you to master the most challenging aspects of your subject.

Conclusion: for growth, tutor students across a wide spectrum. It also allows you to see what constitutes a strong student and what constitutes a weak student.