Forgot about this when I wrote my original post... I went and got a study guide that helped me a lot, it really improved my math score (from a 25 to a 32) by teaching me little tricks on how to recognize the proper answer. Because the test is multimple choice, you can almost always eliminate two of the four answers right off the bat.
Keep in mind too, that the average ACT score is only 21.1. A score of 31 puts you in the 98th percentile... meaning only 2% of people tested will score higher. That's a pretty lofty goal... one I hope you can achieve.