I took my SAT scores from 90th percentile to 98th percentile by buying a book, doing a few sample problems every night for a couple of weeks, and reading the test taking tips in the back. Probably the most helpful tip was that all the math diagrams were drawn to scale.

The bigger benefit of all of this to me was the SATs as another example of how truly arbitrary the world seems to be, and how little extra effort is actually required to curb that arbitrariness towards your goals.