of their sophomore year. This gives them exposure and familiarity with the test. We don't report their scores to these tests anywhere. Then once they start their junior year, I have them take it every testing opportunity that works with their schedule.

Other than the math section, the ACT is not a test of what you know. It's a test of reading skills under timed conditions. The more times you take it, and the more you practice, the better you'll do. If your junior hasn't taken it yet, sign him or her up for every single opportunity between now and October. Get copies of the old tests and practice taking them.

Do daily practice of 5 questions with them, and talk through why the answer is correct (this is especially key for the English section).

PrepScholar has a bunch of really good free articles on keys for doing well on specific subject matter in the test. For example here's one on how to spot and ace the comma questions in the English section: https://blog.prepscholar.com/everything-you-need-to-know-about-commas-for-the-act

There is only one official past test available for free online. The ACT releases a new full test with answer key every few years and then pulls the old test offline and makes it no longer available. I, however, have downloaded the past 4 tests. If you want copies of them, BM me, and I can email them to you. The official tests are the best study tools to use.