As you embark on the journey to master the International English Language Testing System (IELTS), selecting the right instructor is a crucial step. Your instructor will guide your understanding, sharpen your skills, and provide invaluable insight into the exam structure and strategies essential for scoring high. However, choosing an instructor shouldn't be a hasty decision; it requires thoughtful consideration and inquiring discourse.

In this regard, I suggest six pivotal questions that should be a part of your discussion with your potential IELTS Prep instructor. These questions are crafted based on pedagogical theories, psycholinguistics, and the specific demands of IELTS.

1. What is your experience with IELTS and English language teaching?

   Your instructor's experience in the field of IELTS and English language teaching is a determinant of their expertise. Instructors seasoned in pedagogical practice, cognitive development, and language acquisition can adeptly guide you through the linguistic and strategic intricacies of the test. Furthermore, they can leverage their accumulated wisdom to tailor educational interventions based on your learning style and needs.

2. How do you keep abreast of the changes in the IELTS test format and scoring?

   IELTS, much like any standardized test, periodically undergoes modifications in its format and scoring. An instructor who keeps themselves updated with these changes can equip you with up-to-date strategies and advice. This is particularly critical considering the dynamic nature of language learning and testing, both strongly influenced by sociolinguistic trends and technological advancements.

3. How do you approach different sections of the IELTS test?

   Each section of the IELTS test - Listening, Reading, Writing, and Speaking, demands different skills and strategies. It's important to understand your instructor’s approach to teaching each section. An effective instructor should have a holistic teaching method but should also have nuanced strategies for each section. Their approach must be grounded in theories of second language acquisition, cognitive processing, and educational psychology.

4. What resources do you recommend for IELTS Prep?

   IELTS preparation benefits greatly from an array of resources like textbooks, online platforms, and mobile applications. The efficacy of these resources is grounded in their alignment with your learning objectives and the demands of the IELTS test. Your instructor's recommendations for resources can provide valuable insights into their understanding of effective language learning tools and their suitability to your unique learning needs.

5. How do you provide feedback and monitor progress?

   Feedback is a critical component of the learning process. It is through feedback that learners gain insight into their strengths and areas for improvement. Your instructor's feedback must be constructive, timely, and grounded in the principles of formative assessment. Furthermore, the system your instructor uses to monitor your progress should be robust and transparent, enabling you to see your trajectory and strategize accordingly.

6. How do you personalize your teaching to suit individual needs?

   Each learner is unique and brings a different set of skills, strengths, and challenges to the table. Therefore, the instructor’s ability to personalize their teaching to cater to your individual needs is paramount. This is underpinned by the theory of differentiated instruction, which postulates that effective teaching should adapt to the learner's individual profiles.

These questions serve as a comprehensive guide to understand your potential IELTS Prep instructor's qualifications, approach, resources, feedback mechanisms, and capacity for personalized instruction. The responses will assist you in making an informed decision and selecting an instructor who aligns with your learning style, needs, and IELTS goals. The journey to mastering IELTS is challenging but with the right instructor, it can become an enjoyable and enriching experience.