Read both parts of the Drivers License Manual. The Handbook section explains the process of getting a permit and will give you important information about getting and renewing your permit. The Study Guide provides all the subject matter you will be tested on, and it is linked in the Resources Section.
Give yourself ample time to absorb and review the material presented in The Study Guide, as it is just about 60 pages long. Read through it carefully and highlight or underline very important statements. Take notes as you go, as this while help reinforce the information. You do not need any outside sources; every question on the test will be sourced directly from this booklet.
Use reliable methods of study. After reading through The Study Guide, you may want to create an outline of the most important information, so you will have a condensed, portable version that you can review many times. You could give the Guide to a friend and ask them to quiz you and take note of which questions you miss. You could make flashcards with important definitions and rules and review them nightly. The test will be multiple choice (one right answer and three wrong answers) so practice arriving at the right answer by process of elimination.
Take a practice learner's permit test. Four tests -- on Alcohol, Laws, Procedures, and Signs -- are linked to in the Resources Section. Take the test under similar conditions as you would in the DMV (there will probably be background noise and you may be seated in an uncomfortable chair). After checking your answers, review which questions you got wrong, and reread the corresponding section in the Study Guide.
Familiarize yourself with the test format so you won't be surprised by anything on the day of the test. You will not be able to use any written notes, and the exam may be written or computerized (this is not your choice; the format depends on what equipment each DMV branch uses). The test will cover each of these four sections equally: Traffic signs and signals; safe driving principles; rules of the road; and drugs and alcohol. Spend roughly equal amounts of time on each of these broad categories, then begin to pay attention to areas that are completely new to you or especially dense or complicated.