My class ended in the beginning of November and I took my test the following January 3rd. I didn't crack my book the entire time and had no trouble whatsoever with the written portion. I focused all my studying on the skills portion.
The written test, from what they showed us in class, is pretty easy. It's the skills part you need to really prepare for and even then its not 100% sure. Our CNA instructor told us that its very subjective because we don't know what kind of person the examiner is, if she's in a bad mood, etc. I got 100% on both medical term vocab tests and 95% on the NACES practice test and the teacher wanted to know what my study habits were due to acing both vocab tests and I said I watch a **** ton of "E.R.", "House" and "Grey's Anatomy", she said well whatever you're doing keep it up. Lol! We did a practice run with the skills portion, too, where they split the class up and took us by twos into another room and gave us five random skills to do. My partner and I got take and record a radial pulse (I love that skill, its the easiest one for me!), Nail care, dress someone with an affected right arm and transfer from bed to wheelchair. Hand washing was number one but she let us skip it since we went over it so much already. I was so scared I was going mess up bad and my partner said she felt the same when she was doing her turn. I was the patient first. But, I just put the teacher out of my head and acted like my partner really was my patient and breezed through the skills with only a few minor mistakes which I caught first. The teacher wrote down what we needed to work on better before the real deal and mine was following the blue book steps in order, I got a bit off track a few times but still did well enough that the teacher said if I did what I did for my practice skills exam here, except the mistakes, etc, at the big test then I would surely pass. Wait, what was your question? Oh! The written NACES test. Yeah, it's not that hard, plus you can download practice tests online to see kinda what you'll be up against, Good luck!