Instructions
Listen to everything your instructor tells you during your training. This professional has been where you are now, and will be telling you things all during your pilot training which will help you succeed on your exam.
Attend classes regularly, or, if working on your own, read and re-read the textbook. Do the workbook exercises on separate paper so that you can do them repeatedly.
Buy the private pilot written exam preparation manual, which contains any questions that you could be asked in multiple-choice format. Make sure that you have the correct answers for each, and then review them many times.
Utilize web sources which offer free written exam preparation in an interactive format. The more varied your approach to going over the exam questions, the better prepared you will be as a prospective pilot.
Ask someone to quiz you on the written questions. This approach has the added benefit of preparing you for the final checkride, when the pilot examiner will be asking questions while you're flying.
Make a set of flash cards with one question on the side of each card and the correct answer on the other. Go through these cards quickly. If you don't know the answer, place the card in a "don't know" pile. Keep working that "don't know" pile until you know all the answers.