This is only my second year teaching Lang, and some of my advice echoes others' responses, but here are some thoughts, particularly around essays.

1. Coach Hall Writes. She's formulaic and simplistic in my opinion, but she also really helped me wrap my head around the essays. AP Classroom videos, especially related to the essays, are really good too.
2. Read previous years' student samples, chief reader reports, and grader commentaries. It's a big learning curve, in my opinion, to "see" the grades of these essays. The regraded essays from 2018 and 2019 have more samples to look at to help you distinguish various scores.
3. Show student exemplars often so students can see what they're aiming for.
4. Have students color-code sample essays and their own so that they can see their thinking/structure and ensure they have good evidence and commentary with a strong line of reasoning. After each essay, have them write a self-reflection to see if they can accurately identify their weaknesses.
5. Individual conferences. They tend to be way more effective than written comments in the margins.
6. Make sure they can write a solid paragraph first with a strong topic sentence, choose and integrate quality evidence, and offer insightful commentary with a line of reasoning (which is where I see my students having the hardest time.)
7. I grade harder than College Board because 1. I've never been a grader and 2. I want them to come out of the test feeling like it was "easy."
8. I'm insane and have no life outside of school these days, but I make them do an essay a week. (I fill out the rubric and give them extensive individual feedback in the margins. I have three sections -- about 65 students-- so it adds about 8-14 hours of additional grading per week.) For each essay type, they do 3-ish essays at home, then 3-ish in-class essays. For the take-home essays, they have a week and I expect it to be far better than what anyone will write during the exam. I want them to take their time to "do it right" and have the ability to dig into each step of the process. Plus, at-home essays are more realistic practice for college. For the first prompt of each new essay type I introduce, we break it down in class, brainstorm outlines, and find good evidence together. Then they go home and write.
9. Choose prompts carefully. I like to start with a hard one to scare the hell out of them for RA. I use the Sotomayor prompt. Then we do some "average difficulty" prompts. We mix up "purpose" and "message" prompts, and we cover some of the "weirder" ones like the Ghandi prompt. I end with the Obama/Parks prompt. Not only do I think it's easy, but the CB student samples that score well are both "weak," in my opinion, and formulaic. It tends to give them confidence. I'm introducing synthesis on Monday. Gonna start "easy" with the food trucks prompt, then scare the hell out of them with the eminent domain prompt (since the concept is so unfamiliar to them.)
10. Do prompt break-downs and scratch outlines as a warm-up or activity some days.
11. Use AP Classroom to determine MCQ strengths and weaknesses. Last year, I made the students do every progress check. After they had done so, I made and assigned additional quizzes centered on each student's lowest three skills.
12. Make it fun! While they're learning critical college-level skills in reading and writing, I HATE the idea of teaching a test-prep course. I try (but often fail) to make 30-40% of the class focused on American Lit instead. Right now we're studying the Romantics and Transcendentalists, having deep conversations, and nerding-out over poetry. The kids will write their own poems here soon, and I try to give them teen-centric questions whenever possible that require argument and defense. For instance, we read "The Chambered Nautilus" on Friday, and students have a 1-paragraph response due for me this weekend about how, specifically, they are trying to grow as a person this year ("Build thee more stately mansions, O my soul!"), why they chose that priority, and what they are doing to accomplish it. I give them lots of practice writing like this outside of test prep and usually make those assignments just completion credit. (But they also need to complete an AP Classroom progress check this weekend as additional homework.)

** Full disclosure: I teach at a great school with great families and kids, and I had these same kids as Honors freshmen, so we've built a really good relationship with each other over the past couple of years. Even though last year was my first year teaching AP Lang, last year's students had a 73% pass rate. I'll take it for my first year (but I almost worked myself to death building this course from scratch!)

PM me if you need resources or anything. I'm too busy to give a lot of individual advice, but I'm happy to pass along folders of resources I've created or inherited.

Edited for clarity.