AP Physics C
I didn't think that mechanics was that bad... Honestly, if you have taken Physics B and AP Calculus AB, you should be just fine with Mechanics. The only new learning material that you will really need to do is rotational physics which isn't too hard.
As far as preparation goes, I used Princeton Review AP Physics C, it has the material for both AP Physics C tests and has practice material for all of the chapters. I'd really recommend doing all of the practice questions that are at the end of each chapter, they are pretty realistic to the real test.
Otherwise, just make sure that your Calculus skills are still sharp and make sure you have all of the formulas memorized for the multiple choice section.
Quick Tip: If you don't understand something and think that you need more conceptual development, head to Hippocampus and watch some of the videos on the topics that you don't understand very well.
Electricity and Magnetism
Electricity and Magnetism was an interesting experience to say the least. I really thought that AP Art Historywas going to be the hardest test I took this year, but I stood corrected.As far as preparation goes, I used Princeton Review AP Physics C. If I were you, I would head to the College Board website and do all of the old AP questions.Make sure that you know when to apply calculus and how to apply it correctly, that's probably the most important thing.
You should also make sure you understand things conceptually. The test tests you more on the conceptual knowledge of E&M rather than just plug and chug and formulas.