I am not sure what your preparation has consisted of. You likely have used the “Real ACT book” but if not
you might well try it. http://www.actstudent.org/testprep/book.html
Many people also find Barron’s helpful and there are other prep books and many released tests with answer keys: there are links on this website:
http://blog.prepscholar.com/complete-official-act-practice-tests-free-links
There are good online video resources to help you. You might try checking youtube: https://www.youtube.com/playlist?list=PL9B99BD1005632B6D
here are some for math - sample - there are more - this series goes over an entire test:
ACT - Math Section - 2014-2015 Exam - Q.1-10
See video at: https://www.youtube.com/watch?v=wadH2NSLodY
Hope this helps!