What should you be doing in each grade of high school?
Ninth and tenth grade are for course choices and finding what you actually care about. Eleventh is the heavy year: testing, the college list, and the money conversation. Twelfth is applications and decisions. The single biggest lever across all four is the transcript, and it is built one semester at a time.
Ninth and tenth grade
Course selection matters more than anything else here, because sequences compound. A student who wants engineering needs the math to be moving, and that decision gets made in ninth grade whether or not anyone frames it that way. Beyond that, the useful work is exploratory: try things, drop the ones that were somebody else's idea, and let a genuine interest emerge. Colleges are not counting activities. They are looking for evidence that a person made choices.
Eleventh grade
The heaviest year by a wide margin. Testing strategy gets decided and executed, the college list takes shape, visits happen, and grades carry the most weight because they are the last full year most colleges see before deciding. This is also when the family should say out loud what it can afford. That conversation in eleventh grade is a constraint a student can plan around. The same conversation in April of twelfth is a betrayal.
Twelfth grade
Front-loaded and then oddly empty. Essays and applications consume the fall, early deadlines land in November, and then there is a long wait. Two things students underestimate: mid-year grades are reported and do get read, and comparing offers and aid packages in April is real work that deserves more than a weekend.
What does not help
Treating high school as a four year admissions campaign. The students who end up with the best applications are usually the ones who did things because they wanted to, and the ones who burn out are usually the ones managing a portfolio. The transcript is the lever. The rest is a person.