When using a test preparation guide, read the written material included in the guide carefully. Take the sample tests under simulated test conditions, and read any explanations for questions you answered incorrectly.
Do not skip right to the tests, but read the other written material in the preparation guide. Learn what type of questions you can expect to see on the test and helpful hints for answering various types of questions. If the guide contains review material, look over it carefully to make sure you understand the material.
When you take a sample test, put away your phone and other distractions, use only the type of materials allowed during the actual test and stick to the time limits. Doing so gives you your best indication of your potential performance on the test. When you miss a question, find out why you missed it. The guide may contain an explanation, but if it does not, research to find it.
Give yourself plenty of time to prepare. Trying to read through the whole guide the night before is not likely to be very helpful.