The ACT is quite different from the list of tests we take in school; therefore, we need to approach it differently.
Avoid spending too much time on the questions you find hard, as you may run out of time and be forced to rush through the easy questions. When we rush, we make mistakes even on easy questions. If you can’t put your finger on the answer even after a minute on a question, move on. Mark the question so that you remember to return to it later. Complete all the easy questions at a comfortable pace first and collect as many points as you can, so that you rather than waste time struggling with the hard questions. After doing the easy questions first, go back and solve the hard ones. There is no penalty for wrong answers on the ACT, so you must answer all the questions. If you are running out of time or if a question is a real killer, answer it with your Letter of the Day: pick your favourite letter and stick with it. If you’re consistent, you’re more likely to pick up points.
The Process of Elimination is the main strategy for tackling the tough questions on the ACT and avoiding the trap answers. ACT hides the correct answer among tempting wrong ones, but when you cross off just one or two wrong answers, the correct answer can become more obvious. By knowing how the traps are set, you can more easily eliminate the wrong answer choices and get closer to the right answer.
You must approach every section according to your own strengths and weaknesses. Figure out which section is difficult for you; work on it using the right strategies for that section.
For example, in English, you must remember that choosing the most concise answer is often a wise choice. Remember also that ‘No Change’ is the correct answer about 25% of the times it appears – so don’t hesitate to choose it.
In Reading (and also in Science), remember that you don’t need to do the passages in the order in which they appear: you can leave harder passages for later. In English, remember also to always skim the passage first. A good way to skim is by, reading the introductory paragraph, the concluding paragraph, and the first and last sentences of every paragraph.
The Science section is more about Reading and Math than actual Science. Don’t get intimidated by Graphs in Science passages. You don’t have to solve any mathematical equations here. Remember that these are reading passages based on Science.
Your ACT essay must have a clear thesis point, and this must be made clear in the Introductory paragraph itself. You must go on re-stating your thesis point throughout the essay. You must provide solid examples to support your thesis. Decide your examples and jot them down before you start writing the essay.
Take full-length timed practice tests regularly. This helps you get comfortable with the format and know your areas of strengths and weaknesses. You can do section-wise practice for the sections you find hard. Outside the USA, you will take the ACT as a computer-based test, so you must know the online tools available on the test and be thoroughly familiar with how to use the tools.
Here is a factsheet from act.org about the computerised exam.