I used Manhattan prep books and Barons study book. Barons is quite difficult and probably the most similar to the GRE. Manhattan really lays out the concepts and provides a good foundation for harder questions in Barons. Manhattan also has free online tutorials with a girl named Jen. Those were gold; highly recommended. Study as much as you can and make the time spent meaningful, even if its 20 min of math before you go to work make it count. I took the test once and got 54th percentile for quant, 64th verbal and 4.0 AW. I took the test once. I also had never taken standardized test prior.