What are the best practices that a leader can use to indirectly improve student’s academic achievement in secondary schools?

What are the best practices that a leader can use to indirectly improve student’s academic achievement in secondary schools? I have 30 references that I have collected. If there are better ones to include and there is a need to disregard some then that even better that is even be. Attached is my proposal for the review. the only thing i was not clear on was where I collected the articles and the process I used