I have tutored up to and including the Masters level. I have never failed to guide a student to their target grade. I have always begun with an assessment of the tutees level of understanding with regard to a specific subject matter and then crafted lesson plans to strengthen their fundamentals before progressing onto more complex subject matter.
I have found this to be the most effective method, having used it in the past to take a student without mathematics beyond GCSE to Achieve a merit on an MSc level "Statistics & quantitative Techniques" exam. I also like to tailor the experience to be compatible with the most effective learning style for each particular student. I have used more visual means for those with attention difficulties to ensure constant engagement with the subject material.
My subject expertise is advanced quantitative techniques within economics. My MSc thesis focused on the usage on Fractional Calculus and fractal mathematics in order to enrich economic analysis. For example, Using Fractional Calculus allows for one to incorporate memory in economic models, which is simply not possible with traditional integer calculus.
I have always believed that theory and methodology must both be given equal attention in order to foster the greatest understanding of the subject.