Advice from my son, who aced the ACT twice:
The English and reading sections both tend to have questions where none of the answers seem to make any sense. It's important to note that anything that's not entirely true in an answer — even if it's a minor detail — seems to automatically make that answer wrong. If only one answer is completely factually correct, you must choose it, even if it doesn't quite answer the question. Also, the English section is obsessive about comma placement, so that's always a useful topic to review.