I took the general GRE and a subject specific GRE. I recommend preparing by learning the format of the test and the expectations. You can find that in any reasonable study aid. I took a few free practice tests to warm myself up, but I did not use flash cards or other "study aids" to prepare. From my experience, I doubt it would have helped. The test is designed to find the limit of what you know. Since there are so many possible question options, it would not have helped. For example, vocab flash cards and actual test questions only overlap about 5% (not a legit fact, just an approximation by me). So practicing the same things over and over again doesn't do as much for you as simply reading something challenging and actively learning from it.
For the record, I looked up what I got for reference. I took the test in 2011, and my scaled scores were:
Verbal 640 90th%ile
Quant 740 87th%ile
The subject test is much different.
In 2011 I also took the Chemistry subject GRE. For that I studied to my strengths (analytical and physical chem) and just breezed over my weaknesses (organic and synthesis). This was a mistake. It turns out my weaknesses were the majority of the test questions. I was not prepared at all.
I don't know what my score was. I tried to look it up on the GRE website, but I used my undergrad email which no longer exists, and I cannot access it. The important part was my percentile score was in the teens.
I was distraught with the horrible score. I simply chose not to disclose it to the schools I applied to. Instead, I played up my prior work experience in the field and my research experience. The result? I am currently slaving away in my 4th year of the PhD program of the school I wanted.
TL:DR My recommendations are to study by knowing the test format, warming up with a practice or two, and just reading a good book. If you want help on the subject test, I am the wrong man to ask.