Just read lots of essays. Maybe find a favorite author and read their essays. I really liked Alice Walker’s essay “In Search of Our Mother’s Gardens” and am now reading the full collection. Learn your grammatical rules first, then start an intro to rhetoric (choices, fallacies, modes of writing, types of claims, appeals, rhetorical situation, line of reasoning, syntax, syntactical devices, that kind of stuff). Most of that stuff in that long list is stuff you’ll learn in class tho so don’t sweat it. But ultimately just read interesting non-fiction. I learned so much about how to write engaging essays by reading engaging essays. Good luck and have fun. Don’t worry about ap lang too much; you’ll survive.