The second critical decision came in 1979, when reformers required that every teacher earn a fifth-year master’s degree in theory and practice at one of eight state universities—at state expense. From then on, teachers were effectively granted equal status with doctors and lawyers. Applicants began flooding teaching programs, not because the salaries were so high but because autonomy and respect made the job attractive.
This seems extremely important to me. You need to leave the teaching to the teachers. For some reason, people in the US seem to think that it is a cushy job, or that most anyone can do it. In fact, it takes years of practice to become an effective teacher, and most will never become great teachers. It's a professional job that requires a large number of skills. Also, effective teaching and learning is contextual.
Tests do not teach, they only measure what you know and how well you test. Time spent testing is spent in lieu of learning.
Also, private education is the road to class-based childhoods. Private education can be great, but it cannot be great for all. If you don't subsidize the education of the poor, you are damning their kids to a lack of opportunity.