How can I write a good reflection essay about teaching methods?
How you reflect upon teaching methods is going to depend to a large degree upon whether or not you have experience yet as a teacher. If you do, you are able to reflect on your experiences vis-a-vis your use of particular methods. If you do not have experience yet in teaching, a reflection on your experiences as a student would be good. You could also reflect upon both. It can be quite helpful to contemplate the experience on both sides of the desk.
By teaching methods, I am assuming you are talking about various theories such as constructionist or behavioral theories. A reflection on teaching theories is meant to make you think about those theories, what you find helpful as a teacher and/or as a student. You can discuss examples of what worked or did not work for you. You can discuss how one method or another suits your personality better, for as Parker Palmer says, "We teach who we are." It might be that you have noted that different methods work better or worse for different learners or for different content areas. Reflections are meant to be a form of meta-cognition, so that you are thinking about your thinking on these matters. You might have had a visceral feeling of distaste for a particular method. You need to think about why that is the case. You may have tried a method and found it wanting. Discuss that, by all means, and reflect upon why something was not successful for you. Reflecting on our failures is often at least as important as reflecting on our successes.
Remember that a reflection is meant to demonstrate your insights into yourself and your teaching or possibly your insights into yourself as a learner, too. When we are called upon to reflect, it can be a very powerful learning experience.