Prepare your children for the SAT and ACT years in advance!! Please. Please, please, please.
Getting As in school or taking dual-credit classes is not necessarily worth anything. Students too often do not learn their math by heart in the first place, and too often get passed to the next grade even if they didn’t really earn it. (In general, not at every school.)
I see it much, much too often. There is no overcoming a weak foundation — other than lots of hard, rational work.
Drill like heck in algebra, arithmetic, and geometry. Answers should come hard and fast.
Drill like heck in grammar. Proper grammar should be automatized. Students should know parallelism, logical comparison, noun-number agreement, pronoun-antecedent agreement, and more.