Bumping ACT Score

I took the ACT a few months ago and was very upset to receive a 23, considering I am a very diligent student in all advanced/AP courses with a high GPA- it just seemed to soil all of my hard work. I would love to get a 30 eventually, and I know it’s possible, but takes hard work that I am willing to undergo. What are some books and tips that some of you have used to bump your scores?