Go with Mike Holt stuff. The first book I bought there were more mistakes than I can remember. For instance the engineer would try to put code references in his own words. That didn't make sense sometimes because the code is trying to be precise and it takes many iterations to get to be precise. The most blatent mistake I can remember, on a true-or-false question, he tried to claim that receptacles had to be every 6 feet (you know it says that it's within 6 feet of any area along the wall, which calculates to about 10-12 feet). After that one I knew I had to get another book.
Make sure you know which year code they are testing on. It might be the code before this present one, depending on the state and testing agency. I couldn't get any information on anything and I went it alone. Nothing was explained to me from anyone. No one knew, not even the secretaries at the local state bureau of licensing. I studied from the wrong code year and only realized it about 3 weeks before the exam after deciphering some information from their website. What a pain that was!! I crammed on the new material and almost choked on the day of the exam.
It's important to find out how your tests are scored. Some testing requirements in states grade code with less points than calcluations. Code might be worth 1 point out of a total 100 and a calcuation might be 3 to 7 points out of 100 or thereabouts. My state didn't do that but I hear others did.
My suggestion is to get the Mike Holt study guide and other material he might offer for passing the exam. The one I have has 12 chapters. Depending on how long you are out of school or how well you learned school (or not), I suggest one to three chapters a month. There's a lot to take in to polish off your studies to pass your test. That means it can take from 4 to 12 months of study to pass the first time.
Good luck.
Bacchus