I used the study guide
@Chris Arnesen mentioned. It's written in such a way that the answers and questions lend themselves to each other and it works very well. I studied that over a long weekend years ago and it started to make sense of everything. Couple that with one of the practice apps on my iPhone and it was easy to know when I was ready. Another advantage of the app I used is that it shows how you score by section. You might have all of the formulas down for Watts, or Amperage, but not on another subject. The app lets you know so you don't waste time studying something you're well versed in, but kinda clueless on another.
For anyone not making progress studying on their own, the HAM Crams mentioned by
@Simon Wolfe are great from what I hear. You're not learning all of the theory and background needed to be a HAM operator. What you learn is everything needed to pass the test. No more, no less. After 6 or so hours of filling (cramming as it were) your brain, you go straight to taking the test, so it's as fresh as possible. Remember, the license is good for 10 years. And many years ago, in an effort to make it easier for people to get their HAM license, the FCC did away with the Morse Code requirements.
A lot of people build up the test to be this huge insurmountable task that they can never accomplish. Sometimes it seems the hardest thing about the test is finding a time and location that works for you. Pick one a few months away. Study what you can and learn the rest at the cram session. You'll be better prepared than some, and that might just be enough confidence boosting you need to succeed at the test!