Here are some resources:

• My tutoring resources folder containing real SAT / ACT / PSAT tests and book PDFs (email me)

• The College Panda SAT / ACT advice (dozens of good articles)

• SuperMemo Wiki on Learning (the best resource on learning I've seen)

• Cognito Mentoring Wiki

• Learning Wiki

• How to Remember Anything Forever (by Nicky Case)

Reading recommendations for high schoolers:

• Standard reading recommendations to improve your SAT / ACT verbal scores

• Everything on Wikipedia

• Paul Graham's essays: http://www.paulgraham.com/articles.html

• Brian Tomasik's essays: https://briantomasik.com/writings/

• SPARC Book Recommendations. But really, just read anything!