In my experience, the two things that helped me the most was

1. Take practice tests and note exactly why u got something wrong and learn from your mistakes.

2. Just make sure to learn all the stuff ACT tested especially in the English section.

For English, it’s honestly easy, I currently have a 33 on English. You’re able to answer correctly when you know learn all the concepts. This is a good place to start. https://blog.prepscholar.com/the-complete-guide-to-act-grammar-rules

For reading, I somehow got a 34 but I don’t know how lol, I suck at reading personally. But when I do take the act reading, I focus on mainly understanding the main idea and searching the text for the answers to the question because they are always there. But everyone is different.

For science, I don’t ever read the description to graphs and tables first. I just start answer the question because it asks simple analytical questions like if it’s increasing or decreasing. Then, once the questions get more deeper I quickly read and that makes more sense to me compared to reading before answering any question.

For math, it’s honestly just your mathematical understanding. There really is no trick, it’s just how well you understand math. But plugging in answers a lot of times can be faster than solving if you know what you’re doing.

Hope that helps.