BC all the way! Keyholes and TFE were my worst too! What helped me was to go skip to the end of the exam on BC, end it, and review a couple questions at a time, but untimed. Dont look at the answers, but go through them slowly..take as much time as you need! Then once you start to read the explanations and get better, you can do 15 problems/ day and time yourslef...really helped me!
If you have any other questions, or need some advice, shoot me a message..Im more than glad to help!