Go to your local Department of Motor Vehicles and tell them you'd like information on the written portion of the driving test. They'll supply you with a driver's manual which contains all the material from the test.
Read the book cover to cover. Write out portions of the text that appear particularly important to aid with memorization.
Sign up for a local driver's education class. Check with your high school or a local community organization for class information.
Create flash cards highlighting the different road signs covered in the driver's manual. For example, draw out the stop sign, yield sign and the different merging lane signs on the front of a card. On the back put what the sign means.
Run through the flash cards one by one with a partner until you get them all right. Add in other flash cards related to traffic etiquette and turning or parking procedures once you're ready.
Make a multiple choice home version of the quiz based on what you feel is the most important information. Print out a few copies and practice taking your version of the test so that you'll be prepared to take the real thing. DMV.org offers consumers the chance to "prepare for a permit test or sharpen your driving skills, including CDL, Road Sign and Motorcycle Tests" all for free online.
Return to the DMV and ask to take the test. Stay calm and relaxed while you wait.