I have put together a collection of the best AP Calc review books at . In addition to the prep materials there is information about the exam format and links to released questions from previous exams. Work through these questions as well. It really does take practice to do well at these. The more practice you get the more confident you will be.
For AP Chemistry I would recommend an analogous set of materials: any comprehensive general chemistry textbook (such as Brown), AP Chemistry review book (such as Princeton Review), and plenty of AP free-response questions.
The Best AP Calculus Review Books of 2015 | Learnerator Blog
If you already have a general understanding of the subject and are a bit of a self-starter, I'd treat the AP review book, along with the AP course information guide (on the College Board website) as a "syllabus" for your plan of study. Go through the syllabus sequentially and do the relevant readings in the undergraduate textbook. Use MOOC material or online videos to clarify any misunderstandings.
I will be taking AP Physics 1 at my school this upcoming year (to take the AP exam in 2016). I have finished Algebra II and will be taking Pre-Calc simultaneously with AP Physics. I have never done anything with Physics, nor do I have any previous knowledge of the subject, so I am wanting to read something during this summer to help prepare myself (many other students are taking Physics Honors over the summer to prepare). Are there any books that you could recommend me purchasing to help prepare for the course? Also, I am planning on purchasing an AP review book (probably PR?), but those won't be published until the fall, and I was hoping for something to do during the summer.