Elite ACT scorers? Best ACT Math prep?

I usually score around a 28-30. The last 10 questions are incredibly difficult for me. What resources are there for prep?

do SAT math and the REAL ACT book explains a lot for you, even why the wrong answers are wrong.

The last ten questions are usually the hardest. I would use real ACT tests to practice with and review only the
questions you missed or guessed at using the videos on the ACT Quantum website.

http://www.erikthered.com/tutor/act-facts-and-formulas.pdf

This link will definitely help on the harder topics.