Best Way to Study for Three SAT Subject Tests?

Hey, I am a senior and I need to take two SAT subject tests (at least) for the colleges I am applying to. I am going to take Literature, US History, and Chemistry. The next test is on the 21st of January. I want to know the best methods that you guys used to study, because my ACT is average for the schools I am applying to (32) and my GPA isn’t that great after some misfortune I had (around 3.8). I heard Barron’s is the best book, but what techniques did you guys do to get 750+ or perfect on your tests?

Hey,I am an International student.I need a help for Sat Physics and Biology Subject test.What are the best books for studying Physics and Biology.I have already given the test for 2 times but I am not able to get score above 650 for both of them.What should I do to get a score above 750.I studied Barrons and Kaplan books but I am not able to get good score.Can anyone suggest me for it.Thanks

In ancient times, when they were called Achievement tests, the only prep that I did was to complete the high school courses whose material the tests covered. This was at a non-elite public high school where about a third of graduates went to four year colleges at the time.