Tips for hard ACT Math problems?

I always crash and burn at the end of the ACT Math section on the last 15 questions (like, I get maybe one or two of them right). My score has consistently been around a 25, but I'd really like to get it up above a 27. Any advice?

I'm guessing that there are specific content areas tested in the Math section that you haven't spent enough time reviewing. The last fifteen questions tend to deal with more advanced concepts like trigonometry, angle measurements, matrices, and algebraic equations that include absolute value signs and non-real answers. I would go over your practice tests and take stock of which concepts are giving you the most trouble. Which types of questions do you get wrong most frequently and why?

If you know how to do them and you're just falling victim to test anxiety, the solution is probably just additional practice tests. The more comfortable you are with the test, the less likely you are to stumble at the end of the section. If you genuinely don't know how to do the problems you're missing, you should consider getting a review book that provides detailed explanations of all the concepts tested on the ACT Math section. I'd recommend McGraw Hill's Top 50 Skills for ACT Math.