I took the test for a masters without attending a school.
Get an CD exam, and practice. practice. It is essential to know the rule exceptions, internalational versus inland. Might be worth making flash cards for the exceptions, you only get 5 errors out of 50. Be sure you know your way around the CFRs. Good luck.
Where did you get your cd exam from?
lydanynom- I'd bet 3 out of 4 people with auto license couldn't pass the written part of a drivers test without brushing up on the rules.