Hey guys! Just wanted to post a few tips on taking the ACT that I hope will help! I got a 36 last October using the Barron’s ACT prep book, but I know there are many others that are good if not better. Good luck to all of you, you’ll do wonderfully!
My advice for English is pretty straightforward. It’s about grammar and sentence structure, and while 75 questions might seem like a lot it’s really quite manageable if you know your grammar rules. Skip any odd ones you might not know, but this section is pretty self-explanatory.
My advice for math is to immediately skip anything you don’t know. It’s not good to worry about something you don’t know, and each question is worth the same number of points. Spending extra time trying to solve a problem just isn’t worth it. You have 60 minutes for 60 questions, and it starts out being really easy so you should be able to finish most of it. There is no guessing penalty, so go ahead and bubble in anything you don’t have time to finish.
My advice for reading and science is pretty similar. These two are both 35 minutes long and have 40 questions, so really time is of the essence here. You really gotta be in the zone to finish these. If you already know the information in the science passages, don’t read them. I didn’t read at least half of them, and I did just fine. Reading is a little trickier (for me at least). If you’re just about out of time, do the questions that have lines references and ask about vocabulary since you don’t need to read a whole passage to answer those. Then just guess on the rest.
I think one thing many people forget is the importance of your mental preparation the day you take the test. Do something that makes you happy! I have a test routine where I curl my hair, wear my favorite jeans, drink Mountain Dew, and listen to loud music before every major test like the ACT. It puts me in a much better mood and gets my mind moving. So do something like wearing your favorite outfit or eating your favorite breakfast before you go, I promise it can give you the edge you need! 
Best of luck to all of you!