This is a big question, but studies have shown that testing and spacing are the most valuable techniques to learning. That being said, I would:
1. Read the PMBOK and take notes(I do mine in excel). Your notes should be in the form of a questions: What are the key components in a project charter? Break the notes out by knowledge area, process number. New tab for each Knowledge area: Integration, Scope, etc.
2. I made flash-card for each process group (see pmbok. pg. 75 as an example). Highlight unique Inputs, Tools, and Main Outputs (repeat often). Many questions on the PMP will require you to know where you are in the overall process. I generally did this before going to bed.
3. Get the formulas down, I found a great video online that showed how to do the formulas and it was great (write the formulas down every day or so):
Formula Study Guide
4. Take the Prepcast Test - Full Exam and walk away. The next day, review each question. Review the PMBOK to each wrong answer. Answers are categorized by: didn't know guessed, eliminated answers/guessed wrong, eliminated answers/guessed right, knew the answer. The key is to get yourself to have an intuition about the right answer or know the right answer.
5. Post review, add missing info to your notes in #1.
6. Restudy PMBOK questions/notes from #1 (#2 / #3 are iterative).
7. Retake exams. 1 per week worked for me. You should see your grades climb progressively.
I'm studying for the PBA now and passed the PMP recently and I'm doing the same thing for the PBA.