Some of the factors that could be considered when evaluating a teacher's effectiveness include:
* Teaching style: Does the teacher use a variety of teaching methods and resources? Is the teacher able to engage the students and make the material interesting?
* Content knowledge: Does the teacher have a strong understanding of the subject matter? Is the teacher able to answer students' questions clearly and concisely?
* Classroom management: Is the teacher able to maintain a positive and productive learning environment? Is the teacher able to deal with disruptive students effectively?
* Student feedback: What do students say about the teacher? Do students feel that the teacher is helpful and supportive?
Ultimately, the best English teacher for a particular student will depend on the student's individual learning needs and preferences.