As a freshman/sophomore in high school did you take the preliminary ACT aka the PLAN? If so, the ACT you'll be taking now is like that except a little harder. The ACT is actually a much easier test in my opinion than the SAT, but then I took it many many years ago so it might have changed by now. From what I recall, know your math (mainly algebra, geometry, and some trigonometry/precalc), and science, and english. I think the trickiest portion of it was probably the reading since the passages are so damn boring so it requires a lot of focus, kinda like on AP English exams. The writing portion of the ACT is really easy though. But like all tests, make sure you get a good's night rest so you don't get anxious and start forgetting what you know. And remember, answer every single question. It's not like the SAT where you get punished for guessing. Good luck